SSC CGL Tier 1 2021 General Awareness Questions with Solutions

Explanation

Xylem is the specialized vascular tissue in plants responsible for the upward conduction of water and dissolved minerals from the roots to the leaves and other parts of the plant. It consists of four main types of cells: tracheids, vessels, xylem parenchyma, and xylem fibres. Among these, tracheids and vessels are the primary conducting elements, forming a continuous system of hollow tubes that facilitate the bulk flow of water. The transport mechanism in the xylem is driven by physical forces like transpiration pull, which creates a negative pressure or suction that draws water upward, and root pressure, which aids in the initial movement of water from the soil into the vascular system.

Explanation

Veer Surendra Sai was a prominent revolutionary leader from the Sambalpur region of Odisha who fought against British colonial rule. He initiated his resistance in 1827, primarily challenging British interference in the succession of the Sambalpur throne and the later implementation of the Doctrine of Lapse. His struggle is distinguished by its longevity, as he continued his guerrilla warfare through the 1857 Uprising until his eventual surrender in 1862. He spent a significant portion of his life as a political prisoner in Hazaribagh and Asirgarh Fort, becoming a celebrated folk hero in Odia history. In recognition of his contributions to the freedom struggle, the Government of India and the state of Odisha have named several landmarks and institutions after him, including the Veer Surendra Sai Airport in Jharsuguda.

Explanation

Alexander Cunningham was a British army engineer who developed a keen interest in Indian history and archaeology. In 1861, the Archaeological Survey of India was founded under the viceroyalty of Lord Canning, and Cunningham was appointed as the first Archaeological Surveyor. When the survey became a permanent department of the government in 1871, he was designated as its first Director-General. His extensive surveys and excavations of ancient Buddhist sites across northern India laid the foundation for systematic archaeological research in the country, earning him the title of the Father of Indian Archaeology.

Explanation

Siddhartha Gautama attained enlightenment at the age of 35 after intense meditation under a Pipal tree, which is now revered as the Bodhi Tree. This significant event occurred on the banks of the Niranjana River in Bodh Gaya, Bihar. Upon achieving this spiritual awakening, or Nirvana, Siddhartha became the Buddha, meaning the Enlightened One or the Awakened One. The location is now home to the Mahabodhi Temple complex, a major center of pilgrimage for Buddhists worldwide.

Explanation

In 2020, Mercom Capital Group ranked Adani Green Energy Limited (AGEL) as the worlds leading solar energy developer in terms of capacity. The report titled Leading Global Solar PV Developers placed the Indian firm at the top spot based on its total portfolio of operational, under-construction, and awarded solar projects, which amounted to approximately 12.3 GW. This ranking identified AGEL as the largest solar power generation asset owner globally, marking a significant milestone for the Indian renewable energy sector as the company surpassed other major international developers.

Explanation

Flight Lieutenant Bhawna Kanth became the first woman fighter pilot to participate in the Republic Day parade during the 72nd Republic Day celebrations in 2021. She was part of the Indian Air Force tableau that showcased mock-ups of the Light Combat Aircraft Tejas, the Light Combat Helicopter, and the Sukhoi-30 MKI. Commissioned in 2016, she was one of the first three women inducted into the fighter stream of the IAF. Her participation in the parade at Rajpath served as a historic milestone for gender representation in the Indian Armed Forces.

Explanation

The Ecowrap report is a flagship research publication issued by the Economic Research Department of the State Bank of India. It provides in-depth analysis and periodic updates on the Indian economy, covering aspects such as macroeconomic indicators, monetary policy shifts, fiscal developments, and industrial growth. In May 2020, the report gained significant attention for its detailed assessment of the economic disruption caused by the COVID-19 pandemic. This specific edition offered projections regarding the contraction of India's GDP, the impact of the nationwide lockdown on various sectors, and the efficacy of the government's Aatmanirbhar Bharat economic stimulus package. The report is a primary source of economic data and forecasting used by policymakers and financial analysts to understand the domestic economic climate.

Explanation

Arundhati Roy is the author of the book Walking with the Comrades, published in 2011. The work originated as a long-form essay published in Outlook magazine in 2010, documenting her time spent living with Maoist rebels in the dense forests of Chhattisgarh. Roy provides a first-hand account of the daily lives of the guerrillas and the tribal populations caught in the conflict between the state and the insurgents. The book critiques the Indian government's internal security strategies and examines the impact of industrialization and mining interests on the indigenous Adivasi communities and their ancestral lands.

Explanation

The Float Festival, locally known as Teppotsavam, is a significant annual event celebrated in Madurai, Tamil Nadu, during the Tamil month of Thai (January-February). The festival was initiated by King Thirumalai Nayak in the 17th century to commemorate his birth anniversary. During the celebrations, the idols of Goddess Meenakshi and Lord Sundareswarar are taken from the Meenakshi Amman Temple in a grand procession to the Vandiyur Mariamman Teppakulam, one of the largest temple tanks in South India. The deities are placed on a massive, illuminated float decorated with flowers and silks, which is then pulled across the water by thousands of devotees using long ropes, symbolizing the divine grace of the deities.

Explanation

The inaugural Commonwealth Games, originally called the British Empire Games, were held in 1930 in Hamilton, Ontario, Canada. The event was the brainchild of Melville Marks Robinson and featured approximately 400 athletes representing 11 countries. Participants competed in six sports and 59 events, establishing a tradition of multi-sport competition among the nations of the Commonwealth that has continued every four years, with the exception of the period during World War II.

Explanation

Kamet is situated in the Garhwal region of the Himalayas in the Chamoli district of Uttarakhand, India. It stands at an elevation of 7,756 meters above sea level and is the second-highest peak in the Garhwal region, after Nanda Devi. Unlike the other peaks listed, which are located along the border of or entirely within the territory of Nepal, Kamet lies within the Indian state of Uttarakhand.

Explanation

The Virupaksha Temple is located in Hampi, a renowned UNESCO World Heritage Site that served as the capital of the Vijayanagara Empire. Historically and administratively, Hampi is situated within the Ballari district of Karnataka. The temple is dedicated to Lord Virupaksha, a form of Lord Shiva, and is one of the oldest functioning temples in India, with its origins dating back to the 7th century. It underwent significant expansions under the patronage of the Vijayanagara rulers, particularly during the reign of Krishnadevaraya, featuring a magnificent gopuram and intricate Dravidian-style stone carvings.

Explanation

In irrigation engineering, a lift channel is utilized when the natural topography prevents water from flowing by gravity to the fields. This occurs when the command area is situated at a higher elevation than the water source. To overcome this gradient, water is mechanically raised using pumps or other lifting devices and discharged into the lift channel. The water is thus forced to flow against the natural slope of the land through the application of external energy, enabling the irrigation of upland areas that cannot be reached by traditional flow irrigation methods.

Explanation

The Minimum Support Price is a price guarantee mechanism used by the Government of India to protect farmers against excessive falls in price during bumper production years. Announced at the beginning of the sowing season for specific crops, it is based on recommendations from the Commission for Agricultural Costs and Prices. By setting this floor price, the government ensures that farmers can recover their cost of production and maintain a reasonable profit margin, even if market prices fluctuate. If the market rate drops below this level, government agencies like the Food Corporation of India step in to purchase the produce at the stated price, providing a safety net for the agricultural community.

Explanation

Article 63 of the Indian Constitution provides for the office of the Vice-President of India by stating that there shall be a Vice-President of India. This article marks the beginning of the constitutional provisions concerning the Vice-President within Part V, which deals with The Union. The Vice-President holds the second-highest constitutional office in the country and functions as the ex-officio Chairman of the Rajya Sabha. The mandate for this office ensures the continuity of the executive branch, as the Vice-President is also empowered to act as the President in the event of a vacancy due to death, resignation, or removal.

Explanation

Pressure is defined as the physical quantity that represents the force exerted perpendicularly per unit area of a surface. In physics, the total perpendicular force acting on a surface is specifically referred to as thrust. The relationship between these variables is given by the formula P = (F)/(A), where P is pressure, F is the thrust (perpendicular force), and A is the area of the surface. In a liquid, the pressure at any depth or on the surface of a submerged object is determined by dividing the total thrust exerted by the fluid by the contact area over which that thrust is distributed. This calculation yields the pressure in units such as Pascals (Pa), where 1 Pa = 1 N/m².

Explanation

Samuel Hahnemann, a German physician, founded the system of alternative medicine known as homeopathy in the late 18th century. He developed the central doctrine of similia similibus curentur, or like cures like, which posits that a substance causing symptoms in a healthy person can treat similar symptoms in a sick person when administered in highly diluted doses. Hahnemann formalized his theories in his seminal work, Organon of Medicine, published in 1810. He also introduced the practice of potentization, a process of serial dilution and succussion intended to reduce the toxicity of medicinal substances while supposedly increasing their curative power.

Explanation

Seismic waves are energy-carrying vibrations that travel through the Earth's layers, originating from sudden releases of energy such as tectonic movements, volcanic activity, or large-scale explosions. These are classified as elastic waves because they involve the temporary deformation of the medium through which they pass, with the material returning to its original state after the energy has moved through. They are categorized into body waves, which travel through the Earth's interior, and surface waves, which move along the Earth's crust. The detection and analysis of these waves allow scientists to determine the magnitude, location, and nature of the geological or artificial impulse that generated them.

Explanation

The Government of India Act, 1935, marked a significant turning point in India's constitutional history by proposing the establishment of an All India Federation consisting of British Indian provinces and Princely States. It abolished the system of dyarchy at the provincial level and introduced provincial autonomy, which empowered provinces to act as independent units of administration within their defined spheres. To facilitate this federal structure, the Act provided for a clear distribution of legislative powers between the Centre and the provinces through three specific lists: the Federal List, the Provincial List, and the Concurrent List. This division of authority ensured that both levels of government had defined jurisdictions, laying the groundwork for the federal system later adopted in the Indian Constitution.

Explanation

The Gujarat government launched the Mukhyamantri Bagayat Vikas Mission in January 2021 to promote horticulture and medicinal plant farming across the state. This initiative aims to double the income of farmers and increase employment opportunities by converting approximately 50,000 acres of uncultivated government wasteland into productive land for high-value crops. Under the mission, the state provides these wastelands on a 30-year lease to individuals, groups of farmers, or organizations at a nominal rent. The scheme focuses on utilizing advanced agricultural techniques, including drip irrigation and sprinklers, to enhance crop yields in arid and semi-arid regions of the state.

Explanation

In irrigation engineering and agricultural planning, the command area refers to the total geographical region that can be served by a canal system or an irrigation project through the supply of water. This area is defined by the physical reach of the canal network and its distributaries, representing the land that can be irrigated by gravity flow or defined lift mechanisms. The command area is typically classified into the Gross Command Area (GCA), which includes the total area within the project boundary, and the Culturable Command Area (CCA), which identifies the specific portion of the land suitable for cultivation and irrigation. The term signifies the operational jurisdiction and spatial extent of the water delivery infrastructure for both agricultural and other functional water requirements.

Explanation

A radial drainage pattern develops when streams flow outward in all directions from a central elevated point, such as a mountain peak, volcanic cone, or dome-shaped hill. This pattern resembles the spokes of a wheel radiating from a central hub. In India, a prominent example of radial drainage is found in the Amarkantak plateau, where rivers like the Narmada and Son originate from the same highland area and flow in different directions. This pattern typically forms on isolated, symmetrical topographic highs where the slope orientation dictates the outward path of the water following the initial topography of the landform.

Explanation

The Street Theatre and Performing Arts Fellowship scheme was launched by the Delhi Government through its Sahitya Kala Parishad in January 2021. The initiative was designed to provide a platform for approximately 450 artists to showcase their craft and talent in public spaces across the national capital. By offering a monthly stipend to the selected fellows, the scheme aimed to support the artist community while using street theatre as a medium to create social awareness and bring art directly to the people of Delhi.

Explanation

Milk of magnesia is a liquid suspension of magnesium hydroxide Mg(OH)₂, which is a strong base. On the pH scale, which measures the acidity or alkalinity of a substance from 0 to 14, a value of 7 is neutral, while values above 7 indicate basicity. Milk of magnesia has a pH value of approximately 10.5. This high level of alkalinity is due to the presence of hydroxide ions, making it highly effective as an antacid for neutralizing stomach acid.

Explanation

The Little Book of Encouragement was authored by the 14th Dalai Lama and officially released in February 2021. Edited by Renuka Singh and published by Penguin Random House India, the book is a collection of 130 quotes, reflections, and words of wisdom. It was launched to provide spiritual support and mental peace to people struggling with the emotional and social impacts of the COVID-19 pandemic. In the book, the Dalai Lama emphasizes human compassion, the importance of inter-religious harmony, and the need for global cooperation. He also addresses environmental concerns and promotes the idea that true happiness is found through inner mindfulness and kindness toward others.

Explanation

The Ministry of Housing and Urban Affairs launched the Pradhan Mantri Street Vendor’s AtmaNirbhar Nidhi (PM SVANidhi) on June 1, 2020. This micro-credit scheme was introduced as a part of the AtmaNirbhar Bharat Abhiyan to provide relief to street vendors whose livelihoods were adversely affected by the COVID-19 lockdown. The scheme facilitates collateral-free working capital loans of up to Rs 10,000 to help vendors resume their businesses in urban, peri-urban, and rural areas. It also incentivizes digital transactions and rewards timely repayment with an interest subsidy of 7 percent per annum.

Explanation

Homeostasis is the physiological process by which a living organism maintains a stable internal environment despite fluctuations in the external world. It involves a complex system of self-regulating mechanisms, primarily negative feedback loops, that monitor and adjust internal variables such as body temperature, blood glucose levels, and fluid balance. This state of dynamic equilibrium ensures that the internal conditions remain within a narrow, functional range necessary for the organism's survival and optimal cellular function. By detecting deviations from a set point and initiating corrective responses, the organism can counteract environmental stresses and maintain its biological integrity.

Explanation

Convergent boundaries are characterized by the motion of tectonic plates toward one another, leading to collisions and crustal deformation. When two plates converge, the denser lithospheric plate is often forced downward into the mantle beneath the less dense plate in a process called subduction. This interaction typically results in significant geological activity, including the formation of deep-sea trenches, mountain building, and volcanic arcs. The subducted material eventually melts within the asthenosphere, contributing to the recycling of the Earth's crust.

Explanation

Muhammad Ghori captured the fortress of Tabarhinda (modern-day Bathinda) in 1191, which served as a vital strategic frontier outpost for the kingdom of Prithviraj Chauhan. The loss of this fort posed a direct threat to the Chahamana heartlands of Delhi and Ajmer. This territorial provocation compelled Prithviraj Chauhan to mobilize his forces and march towards the plains of Tarain to confront the Ghorid invaders. The subsequent conflict, known as the First Battle of Tarain, resulted in a decisive victory for Prithviraj Chauhan and the temporary retreat of Muhammad Ghori.

Explanation

The Seventh Schedule of the Indian Constitution, formulated under Article 246, establishes the legislative jurisdiction of the Union and the State governments. It divides subjects into three distinct lists: List I (Union List), List II (State List), and List III (Concurrent List). The Union List contains matters of national importance such as defense and foreign affairs, the State List covers subjects like police and public health, and the Concurrent List includes areas like education and marriage where both levels of government can legislate. This system provides a structured division of powers to ensure functional clarity within India's federal framework.

Explanation

Saudi Arabia held the G20 presidency in 2020 and hosted the 15th G20 Leaders' Summit on November 20 and 21. Although the summit was originally intended to be held in Riyadh, it was transitioned to a virtual format due to the COVID-19 pandemic. King Salman bin Abdulaziz Al Saud presided over the sessions, which focused on the theme Realizing Opportunities of the 21st Century For All. The discussions were heavily centered on global health cooperation, economic recovery strategies, and providing debt relief for the world's poorest countries through the Debt Service Suspension Initiative.

Explanation

Auxins are a class of plant hormones produced primarily in the shoot apical meristems and young leaves. They play a critical role in regulating plant growth by promoting cell elongation in stems. This process is explained by the acid growth hypothesis, where auxins stimulate proton pumps in the plasma membrane to pump hydrogen ions into the cell wall. The resulting decrease in pH activates enzymes called expansins that loosen the chemical bonds in the cellulose of the cell wall. As the cell wall becomes more flexible, internal turgor pressure causes the cell to expand and elongate. This specific action of auxin is the fundamental mechanism behind apical dominance and tropisms, such as phototropism, where the hormone accumulates on the shaded side of a stem to cause differential elongation and bending toward light.

Explanation

Douglas Stuart was awarded the 2020 Booker Prize for his debut novel Shuggie Bain. The book is a semi-autobiographical work set in 1980s Glasgow during a period of industrial decline and economic hardship. It explores the relationship between a young boy named Shuggie and his mother, Agnes Bain, as she struggles with alcoholism and abandonment. Stuart became the second Scottish author to win the prize in its history, and the novel was praised by the judges for its intimacy, grit, and emotional impact.

Explanation

As per Major Rock Edict XIII, Ashoka conquered the region of Kalinga eight years after his coronation (abhisheka). This edict provides a detailed account of the war, mentioning the immense suffering it caused, including the deportation of 150,000 people and the death of 100,000 others. The profound remorse Ashoka felt after witnessing the carnage led him to abandon military conquest (Bherighosha) in favor of cultural and moral conquest (Dhammaghosha), marking a significant turning point in his reign and the history of the Mauryan Empire.

Explanation

The Indian Forest Act, 1927 was enacted as a consolidating statute to streamline the laws relating to forests, the transit of forest-produce, and the duties leviable on timber. Under Section 85 of the 1927 Act, the Indian Forest Act, 1878 (Act VII of 1878) and its subsequent amending acts were repealed. The 1878 Act had previously replaced the initial 1865 legislation to provide a more comprehensive legal framework for the British colonial administration to regulate and classify forests into reserved, protected, and village forests. The 1927 Act largely retained the structure and provisions of the 1878 Act while formalizing the consolidation of forest jurisprudence into a single primary document.

Explanation

The Badminton World Federation (BWF) is the international governing body for the sport of badminton, recognized by the International Olympic Committee. Since October 2005, its global headquarters have been located in Kuala Lumpur, Malaysia. The organization was originally founded in 1934 as the International Badminton Federation and was headquartered in the United Kingdom for many years before relocating to its current Malaysian base to oversee global operations, tournaments, and world rankings.

Explanation

In January 2021, Facebook Inc. appointed Henry Moniz as its first-ever Chief Compliance Officer. Moniz joined the tech giant from ViacomCBS, where he had served as the Chief Compliance Officer and Chief Audit Executive. In his role at Facebook, he was tasked with leading the global compliance team, overseeing the company's compliance and ethics programs, and reporting directly to the general counsel as well as the Audit and Risk Oversight Committee of the Board of Directors. This appointment was a strategic move by the company to enhance its internal governance and navigate complex global regulatory environments and legal scrutiny more effectively.

Explanation

The Third Buddhist Council was convened by Emperor Ashoka in 250 BCE at Pataliputra, the capital of the Mauryan Empire. This assembly was presided over by the monk Moggaliputta Tissa. The primary objective of the council was to purify the Buddhist Sangha from corruption and the influence of heretical sects that had joined the order for royal patronage. During this council, the Abhidhamma Pitaka was finalized and added to the Buddhist canon, completing the Tripitaka. Following the conclusion of the council, Ashoka sent various missions to spread Buddhism across India and to foreign lands such as Sri Lanka, Greece, and Southeast Asia.

Explanation

Jwala Gutta became the first Indian badminton player to qualify for two events in a single edition of the Olympics during the 2012 London Games. She earned her qualification in the women's doubles category alongside her partner Ashwini Ponnappa and in the mixed doubles category with V. Diju. A specialist in the doubles format, she remains one of India's most successful doubles players, having also won a gold medal at the 2010 Commonwealth Games and a bronze at the 2011 World Championships.

Explanation

The Global Innovation Index (GII) is an annual ranking that measures the innovation performance of countries and economies worldwide. For several years leading up to 2021, the index was co-published by the World Intellectual Property Organization (WIPO), Cornell University, and INSEAD. This collaborative effort evaluates approximately 80 indicators, including measures of human capital, institutions, infrastructure, and market sophistication. By combining academic research from Cornell and INSEAD with the institutional data and global reach of WIPO, the index provides a comprehensive benchmark for policymakers and businesses to gauge the strengths and weaknesses of national innovation systems across more than 130 economies.

Explanation

Panche is the traditional attire for men in Karnataka, consisting of a rectangular piece of unstitched cloth, typically made of cotton or silk, wrapped around the waist and legs. It is essentially a style of dhoti or sarong and is usually white or off-white in color. In Kannada culture, wearing a Panche is a sign of elegance and is the standard dress for formal occasions, weddings, and religious ceremonies. It is often paired with a Shalya, which is a matching piece of cloth draped over the shoulders to complete the traditional ensemble.

Explanation

An electrode is a conductor that facilitates the passage of electric current into or out of a non-metallic part of a circuit, such as a patient's body in a medical context. These devices are typically made of conductive materials like metal plates or needles and are essential for both diagnostic and therapeutic purposes. For example, in electrocardiograms (ECG) or electroencephalograms (EEG), electrodes detect natural electrical signals from the heart or brain. In surgical applications, such as electrosurgery or cauterization, they deliver high-frequency electrical energy to target tissues to cut, coagulate, or ablate them during a procedure.

Explanation

In vector algebra, any vector that has a non-zero magnitude is defined as a proper vector. This classification distinguishes such vectors from the null or zero vector, which has a magnitude of zero and no specific direction. A proper vector possesses both a definite numerical value for its magnitude and a specific direction in space, allowing it to represent physical quantities like force, velocity, or displacement effectively. Consequently, every vector that is not a null vector is referred to as a proper vector.

Explanation

Article 198 of the Constitution of India specifies the special procedure in respect of Money Bills in the State Legislatures. Clause (1) of this Article explicitly mandates that a Money Bill shall not be introduced in a Legislative Council. In states having a bicameral legislature, a Money Bill can only be introduced in the Legislative Assembly. After a Money Bill has been passed by the Legislative Assembly, it is transmitted to the Legislative Council for its recommendations. The Legislative Council must return the Bill to the Legislative Assembly within a period of fourteen days from the date of its receipt. The Legislative Assembly may then either accept or reject any or all of the recommendations made by the Legislative Council. If the Legislative Council fails to return the Bill within the stipulated fourteen days, the Bill is deemed to have been passed by both Houses in the form in which it was passed by the Legislative Assembly.

Explanation

Distillation is a purification process based on the principle of phase changes and differences in volatility. When impure water is heated to its boiling point, it transitions into water vapor or steam. Most solid contaminants, salts, and minerals have significantly higher boiling points than water and do not evaporate, remaining in the original vessel. The resulting steam is then channeled into a condenser, where it is cooled and converted back into liquid form. This purified liquid is collected in a separate container, leaving the non-volatile impurities behind.

Explanation

Madhya Pradesh became the first state in India to implement the Direct Benefit Transfer (DBT) for electricity subsidies as part of the power sector reforms introduced by the Ministry of Finance. The scheme was initially launched in the Vidisha district in January 2021, where the electricity subsidy is transferred directly into the bank accounts of the beneficiary farmers. By successfully implementing this reform, Madhya Pradesh fulfilled one of the mandatory conditions set by the central government for power sector reforms, thereby becoming eligible for additional borrowing equivalent to 0.15 percent of its Gross State Domestic Product (GSDP). This transition aimed to improve transparency, reduce leakages, and ensure better targeting of subsidies in the agricultural sector.

Explanation

Prithviraj Chauhan and Muhammad Ghori fought the historic Battles of Tarain near Karnal in modern-day Haryana. The First Battle of Tarain occurred in 1191, resulting in a victory for the Rajput ruler Prithviraj Chauhan and the temporary retreat of the Ghurid forces. The two leaders met again at the same site in 1192 for the Second Battle of Tarain. In this subsequent encounter, Muhammad Ghori secured a decisive victory over the Rajput confederacy. This outcome was a major turning point in Indian history, as it cleared the way for the establishment of the Delhi Sultanate and the expansion of Ghurid rule across northern India.

Explanation

Anai Mudi, also known as Anamudi, stands at an elevation of 2,695 meters (8,842 feet) and is the highest peak in the Western Ghats and the entire South Indian peninsula. It is located in the Idukki district of Kerala, within the Eravikulam National Park. The peak is situated at the junction of the Anaimalai Hills, the Cardamom Hills, and the Palani Hills. Due to its significant height and prominence in the Deccan Plateau region, it is often referred to as the Everest of South India. The name Anai Mudi translates to Elephant Head in Malayalam, describing the physical appearance of the mountain.

Explanation

Magnesium is a chemical element with the atomic number 12 and belongs to the alkaline earth metal group in the periodic table. The International Union of Pure and Applied Chemistry (IUPAC) assigns the symbol Mg to magnesium, which is derived from the first and third letters of its name. In its pure form, magnesium is a shiny gray solid that is highly reactive and essential for various biological and industrial processes.

Explanation

In the modern periodic table, elements are arranged in increasing order of their atomic numbers. The horizontal rows are known as periods. There are a total of seven periods, numbered from 1 to 7. The period number of an element corresponds to the highest principal quantum number n of the electrons in its atoms, which represents the number of electron shells being filled. For example, elements in the second period have their valence electrons in the second energy level (n = 2). Moving across a period from left to right, the number of valence electrons increases, leading to a periodic variation in chemical and physical properties.