Defence Minister Nirmala Sitharaman paid a three-day official visit to Kazakhstan from 1 to 3 October 2018 to strengthen bilateral defence and military-technical cooperation.

In October 2018, the Parliament of Canada unanimously voted to revoke the honorary Canadian citizenship bestowed on Myanmar leader Aung San Suu Kyi in 2007 over the Rohingya crisis.

• Trade Bloc: The North American Free Trade Agreement (NAFTA, now USMCA) was signed between the United States, Canada, and Mexico. Great Britain is not part of it.

India and France signed an implementation agreement on 'Mobilise Your City' (MYC) on 6 September 2018 to support sustainable urban transport and reduce greenhouse gas emissions in Nagpur, Kochi, and Ahmedabad.

External Affairs Minister Sushma Swaraj inaugurated the 'Panini Language Laboratory' at the Mahatma Gandhi Institute in Mauritius in August 2018 during the 11th World Hindi Conference.

In August 2018, the United Kingdom announced a presumed-consent 'opt-out' organ and tissue donation law to address the acute shortage of organ donors for ethnic minorities, particularly people of Indian origin.

Emmerson Mnangagwa succeeded Robert Mugabe as President of Zimbabwe in November 2017 and won the subsequent presidential election held in July 2018.

Turkey lifted its two-year state of emergency on 19–20 July 2018, which had been imposed following the failed military coup attempt in July 2016.

Papua New Guinea declared a national public health emergency in June 2018 after confirming an outbreak of vaccine-derived poliovirus after 18 polio-free years.

By defeating Bangladesh in the final in Dubai on 28–29 September 2018, India won the Cricket Asia Cup for the seventh time (1984, 1988, 1990–91, 1995, 2010, 2016, and 2018).

At the conclusion of the 18th Asian Games 2018 in Jakarta–Palembang, India finished eighth in the medal tally with 15 Gold, 24 Silver, and 30 Bronze medals, totaling 69 medals.

SpiceJet operated India's first test flight powered by bio-jet fuel (a blend of 25% Jatropha-based biofuel and 75% ATF) between Dehradun and Delhi on 27 August 2018.

In June 2018, the World Bank approved a ₹6,000 crore central sector scheme, Atal Bhujal Yojana (ABHY), for sustainable groundwater management across seven states in India.

• Paleoclimatology & Archaeology: Researchers from IIT Kharagpur published a paleoclimatic study demonstrating that an intense and continuous 900-year drought caused by weak monsoons led to the decline and migration of the Indus Valley Civilization around 4,350 years ago.

According to the India State of Forest Report (ISFR) 2017 (released in February 2018), India's total forest and tree cover stood at 24.39% (approx. 24.40%) of the geographical area, with forest cover alone at 21.54%.

Under the Sikkim Forest Tree (Amity & Reverence) Rules notified in 2017–2018, the Sikkim government allowed citizens to forge a 'Mith/Mitini' or brother-sister relationship with trees to conserve them.

Satara district in Maharashtra was ranked first among all districts in India in the 'Swachh Survekshan Grameen, 2018', while Haryana was ranked the top state.

Ayushman Bharat – Pradhan Mantri Jan Arogya Yojana (PM-JAY), launched by PM Narendra Modi in Ranchi on 23 September 2018, is the world's largest government-funded health assurance scheme providing ₹5 lakh cover per family per year.

India's first railway university, the National Rail and Transportation Institute (NRTI, now Gati Shakti Vishwavidyalaya), began operations in September 2018 at the National Academy of Indian Railways (NAIR) in Vadodara, Gujarat.

JIMEX 2018 was the third edition of the bilateral Japan-India Maritime Exercise conducted between the Indian Navy and the Japan Maritime Self-Defense Force off Visakhapatnam in October 2018.

In September 2018, the air pollution control device WAYU (Wind Augmentation Purifying Unit), developed by CSIR-NEERI, was inaugurated at ITO and Mukarba Chowk in Delhi.

Bihar Chief Minister Nitish Kumar inaugurated and laid the foundation stones for more than 750 development schemes in Begusarai and Khagaria on 6 January 2018 during his statewide 'Vikas Samiksha Yatra'.

Deputy Chief Minister Sushil Kumar Modi inaugurated Bihar's first 'Start-up Hub' at Biscomaun Bhawan in Patna on 16 March 2018 to provide free plug-and-play office space to emerging entrepreneurs.

Vice President M. Venkaiah Naidu unveiled the book 'Neel Ke Dhabbe' in Patna on 22 March 2018 during the 106th Bihar Diwas celebrations Marking the centenary of the Champaran Satyagraha.

Prime Minister Narendra Modi flagged off India's first 12,000 HP heavy-haul electric locomotive (WAG-12) built at the Madhepura Electric Locomotive Factory in Bihar (a joint venture with Alstom of France) in April 2018.

On 10 April 2018, Prime Minister Narendra Modi addressed the National Convention of Swachhagrahis under the 'Satyagraha se Swachhagraha' campaign at Motihari in East Champaran district.

The National Disaster Management Authority (NDMA) conducted a five-day training and mock drill on Chemical, Biological, Radiological, and Nuclear (CBRN) emergencies at Lok Nayak Jayaprakash Narayan (LNJP) Airport, Patna in April 2018.

According to OpenSignal's report for December 2017 – February 2018, Patna ranked first among India's 20 largest cities in 4G network availability with 92.6% coverage.

• Clean Water Project: Sulabh International launched its innovative cheapest drinking water project 'Sulabh Jal' in Darbhanga, Bihar, purifying contaminated pond/river water into safe drinking water at just 50 paise per litre.

• Bihar Welfare Scheme: Under Mukhyamantri Kanya Utthan Yojana, total financial assistance from birth to graduation is up to ₹54,100 (raised to approx. ₹50,000 graduation incentive alone), not ₹60,000.

Correct Answer: Option (D) — Mehrgarh • Archaeological Site: Mehrgarh, located on the Bolan River in the Kachi plain of Balochistan, has yielded the earliest evidence of settled agriculture (wheat and barley cultivation) and cattle/sheep domestication in the Indian subcontinent, dating back to c. 7000 BCE.

Correct Answer: Option (C) — Rajgriha (Rajgir) • First Buddhist Council: Held in 483 BCE at the Sattapanni Cave in Rajgriha, the capital of Magadha, immediately following the Mahaparinirvana of Buddha. • Patronage & Presidency: Patronized by King Ajatashatru of the Haryanka dynasty and presided over by Mahakashyapa. • Outcome: Compilation of the Sutta Pitaka (recited by Ananda) and Vinaya Pitaka (recited by Upali).

• Ancient Numismatics: Kushana ruler Vima Kadphises was the first emperor in Indian history to issue high-purity gold coins on a large scale, featuring depictions of Lord Shiva and Maheshvara titles.

In his treatise Aryabhatiya (499 CE), the ancient Indian mathematician-astronomer Aryabhata was the first to state that the Earth rotates on its own axis, causing the apparent daily rising and setting of the Sun and stars.

• Balaputradeva of Suvarnabhumi: The Sailendra dynasty king of Suvarnabhumi (Sumatra/Java, Indonesia) built a magnificent monastery at Nalanda for pilgrims and scholars from his country.
• Devapala's Copper Plate Grant: He sent an emissary to Pala King Devapala (9th century CE), who granted five villages for the maintenance of the monastery and its resident monks, as recorded in the famous Nalanda Copper Plate of Devapala.

• Ancient Maritime Literature: 'The Periplus of the Erythraean Sea' (c. 1st century CE) was written in Koine Greek by an anonymous Greek-Egyptian navigator describing navigation and trading opportunities from Roman Egyptian ports along the Red Sea, Horn of Africa, and Indian coast.

The earliest detailed account of Ikhtiyar-ud-Din Muhammad Bakhtiyar Khilji's invasion of Bihar and the destruction of Odantapuri and Nalanda is given by Minhaj-i-Siraj in his Persian chronicle Tabaqat-i-Nasiri (completed in 1260 CE).

• Delhi Sultanate Agrarian Reforms: Sultan Alauddin Khilji introduced measurement of land (Masahet) and fixed the state revenue demand at half (50% or Kharaj) of the agricultural yield, ruthlessly eliminating intermediary perquisites of Khuts and Muqaddams.

Correct Answer: Option (A) — Suhrawardi Silsilah • Sufism in India: Shaikh Bahauddin Zakariya (1170–1262) was the founder and primary exponent of the Suhrawardi Sufi Silsilah in India, centered at Multan.

• Sur Empire Military Organization: Islam Shah Sur (son and successor of Sher Shah Suri) reformed the Sur military by dividing his troops into organized units of 50, 200, 250, and 500 under designated commanders.

• Foreign Travellers: English merchant and traveller William Finch, who visited India during 1608–1611, described the massive Palace of Forty Pillars (Chihil Sutun) in the Allahabad Fort, stating that 5,000 to 20,000 workmen worked on it for forty years.

• Medieval Kashmir: Sultan Zain-ul-Abidin (reigned 1420–1470), affectionately called 'Bud Shah' (Great Sultan), is celebrated as the 'Akbar of Kashmir' for his broad religious tolerance, abolition of jizya, promotion of Sanskrit literature, and public welfare works.

Haji Shariatullah founded the Faraizi Movement in Eastern Bengal in 1818 to urge Muslims to give up un-Islamic practices and perform their obligatory religious duties (Faraiz).

Dadabhai Naoroji, known as the 'Grand Old Man of India', authored the book 'Poverty and Un-British Rule in India' (published in 1901), in which he propounded the 'Drain of Wealth' theory.

• Land Revenue Legislation: The Bengal Tenancy Act VIII of 1885 defined the rights, tenures, and liabilities of ryots and settled raiyats in Bengal and Bihar, providing protection against arbitrary evictions and uninhibited rent enhancements.

• Formation of Bihar: Bihar was officially separated from the Bengal Presidency and established as a separate province (along with Orissa) on 22 March / 1 April 1912.

• Champaran Satyagraha: Raj Kumar Shukla, a local indigo farmer from Champaran, met Mahatma Gandhi at the 1916 Lucknow session of the Indian National Congress and persuaded him to visit Champaran.

• Lahore Congress Session 1929: At midnight on 31 December 1929 on the banks of the Ravi River in Lahore, Congress President Jawaharlal Nehru unfurled the tricolor flag of Indian independence following the adoption of the historic 'Purna Swaraj' resolution.

• Socialist History of Bihar: The Bihar Socialist Party was originally founded in July 1931 by Phulan Prasad Varma and Jayaprakash Narayan (and later formalised at Anjuman Islamia Hall in 1934 under Acharya Narendra Deva).

• Provincial Autonomy 1937: Following the 1937 elections under the 1935 Act, Dr. Shri Krishna Sinha formed the first Congress ministry in Bihar on 20 July 1937, serving as Premier (Chief Minister) with Anugrah Narayan Sinha as Finance Minister.

• European Geography: Hungary is completely surrounded by land (bordered by Austria, Slovakia, Ukraine, Romania, Serbia, Croatia, Slovenia) with no access to any sea or ocean. Belgium, Romania, and Ukraine all have coastlines.

• Physical Geography: Among the given options, Borneo (approx. 751,930 km², 3rd largest in the world after Greenland and New Guinea) is larger than Madagascar (~587,000 km²), Sumatra (~473,000 km²), and Great Britain (~209,000 km²).

The Pampas region of Argentina and Uruguay lies on the eastern coast of South America and experiences a temperate grassland / humid subtropical climate, whereas Central Chile, Cape Town, and Adelaide have a Mediterranean climate.

Correct Answer: Option (B) — China • Sericulture Data: China is the world's leading producer of raw silk, accounting for over 70% to 75% of global silk output. India is the second-largest producer and the largest consumer of silk globally.

• Energy Statistics: According to global energy statistics, after the United States, Russia and Saudi Arabia alternate as the second and third largest crude oil producers globally.

The Garo, Khasi, and Jaintia Hills (along with the Mikir Hills) form part of the Meghalaya-Karbi Anglong Plateau, whereas the Bhuban Hills are part of the Purvanchal (Barail/Mizo) range in Assam's Barak Valley.

Among the given passes, Nathu La in Sikkim is at the highest elevation (~4,310 m / 14,140 ft), higher than Rohtang Pass (~3,978 m), Zoji La (~3,528 m), and Khyber Pass (~1,070 m).

• Geographical Context: Karewas are thick lacustrine deposits of clay, silt, and moraines found in the Kashmir Valley between the Great Himalayas and the Pir Panjal Range. They provide exceptionally fertile soil uniquely suited for cultivating Zafran (Kashmiri saffron), almonds, and walnuts.

According to the 2011 Census of India, the urban population accounted for 31.16% (approximately 31%) of the country's total population, while the rural population was 68.84%.

• NITI Aayog Full Form: NITI stands for 'National Institution for Transforming India', established via Cabinet resolution on 1 January 2015 to replace the Planning Commission.

Correct Answer: Option (C) — 1956 • States Reorganisation Act: Based on the recommendations of the Fazal Ali Commission, the Parliament passed the States Reorganisation Act in 1956, reorganizing Indian states predominantly along linguistic boundaries into 14 states and 6 Union Territories.

• Agricultural Geography: Uttar Pradesh is historically known as the 'Sugar Bowl of India' due to having the largest acreage under sugarcane cultivation and massive sugar production.

• Mineral Wealth of India: India has historically been the undisputed world leader in the production and export of sheet mica, with prime deposits in the mica belt of Koderma-Giridih (Jharkhand) and Nellore (Andhra Pradesh).

• Formation History: Following the proclamation of Emperor George V at the Delhi Durbar in December 1911, the Province of Bihar and Orissa was officially separated from the Bengal Presidency on March 22, 1912, which is celebrated annually as 'Bihar Diwas'.
• Subsequent Milestones: Orissa was separated from Bihar in 1936, and Jharkhand was carved out on November 15, 2000.

• Geology of Bihar: Kharagpur Hills (Munger) belong to the Dharwar rock system (Precambrian, ~2500–1600 Ma), which is older than the Vindhyan rocks of Rohtas Plateau (Mesoproterozoic) and the Quaternary Ganga Plains.

Patna district shares its borders with 9 districts of Bihar: Bhojpur, Saran, Vaishali, Samastipur, Begusarai, Lakhisarai, Nalanda, Jehanabad, and Arwal.

• Soil Distribution in Bihar: Over 90% of Bihar's geographical area lies in the fertile Gangetic plain formed by quaternary alluvial deposits brought down by the Ganga and its tributaries, comprising Khadar (new alluvium) and Bhangar (old alluvium).

• Census 2011: In terms of having the lowest literacy rate, Bihar ranks 1st (at the absolute bottom of all Indian states with a literacy rate of 61.80%).

• Agricultural Production: West Bengal ranks first in jute production in India, while Bihar ranks second (primarily concentrated in Purnia, Katihar, and Kishanganj districts).

Because of its fertile Gangetic plains, abundant water resources, and high agricultural production of grains, fruits, and vegetables, agro-based and food-processing industries have the highest potential in Bihar.

• Constitutional Resignation: Under Article 124(2)(a) of the Constitution of India, a Judge of the Supreme Court may, by writing under his hand addressed to the President, resign his office.

Correct Answer: Option (B) — Kaka Saheb Kalelkar

• Constitutional Appointment: Under Article 316(1) of the Constitution of India, the Chairman and other members of a State Public Service Commission are appointed by the Governor of the State (though they can only be removed by the President under Article 317).

• Constitutional Qualification: Under Article 84(b) of the Constitution of India, a citizen must be not less than 25 years of age to qualify for election to the House of the People (Lok Sabha).

• Constitutional Mandate: Under Article 155 of the Constitution of India, the Governor of a State is appointed by the President by warrant under his hand and seal, and holds office during the pleasure of the President (Article 156).

Article 330 of the Indian Constitution provides for the reservation of seats for Scheduled Castes and Scheduled Tribes in the House of the People (Lok Sabha), whereas Article 332 deals with State Legislative Assemblies.

Correct Answer: Option (B) — is an integral part of the Parliament • Article 79: Under Article 79 of the Indian Constitution, the Parliament of the Union consists of the President and two Houses (the Council of States / Rajya Sabha and the House of the People / Lok Sabha).

• Gandhian Principles (DPSP): Article 40 of the Constitution directs that: 'The State shall take steps to organise village panchayats and endow them with such powers and authority as may be necessary to enable them to function as units of self-government.'

The State of Jharkhand was carved out of southern Bihar on 15 November 2000 (the birth anniversary of Birsa Munda) as the 28th state of India under the Bihar Reorganisation Act, 2000.

• Centre-State Relations: The Sarkaria Commission, set up in June 1983 under Justice R.S. Sarkaria, finalized and submitted its comprehensive 1,600-page report to Prime Minister Rajiv Gandhi on 27 October 1987 (officially released in January 1988).

• Constitutional Bodies: Under Article 280 of the Constitution of India, the President constitutes a Finance Commission every fifth year (or earlier) to recommend the distribution of net tax proceeds between the Union and the States.

Under Article 76(1) of the Constitution of India, the Attorney General of India is appointed by the President of India and holds office during the pleasure of the President.

• Planning Commission Target: The Twelfth Five-Year Plan (2012–2017) explicitly fixed an average annual growth rate target of 4.0% for the agriculture and allied sector to ensure food security and inclusive growth.

• Industrial Policy: Launched in September 2014, the 'Make in India' initiative aims to transform India into a global manufacturing hub by lowering transaction and logistics costs, simplifying regulatory procedures, and boosting investment.

• Industrial Policy: Make in India, Start-up India, and Ease of Doing Business directly target industrial and manufacturing growth, whereas Digital India is primarily a tech infrastructure and citizen e-governance initiative.

Former President Dr. A. P. J. Abdul Kalam propounded the PURA (Providing Urban Amenities in Rural Areas) strategy in his book 'Target 3 Billion' to bridge the rural-urban divide through physical, electronic, and knowledge connectivity.

Correct Answer: Option (C) — 65.5 percent (official 65.46%) • Census Findings: In the 2011 Census of India, the female literacy rate in India stood at 65.46% (rounded to 65.5%), compared to a male literacy rate of 82.14% and total overall literacy of 74.04%.

Nobel Peace Prize laureate Professor Muhammad Yunus pioneered the concept of microcredit and community-based Self-Help Groups (SHGs) through the Grameen Bank in Bangladesh to alleviate poverty.

• Central Bank Leadership: Urjit Patel served as the 24th Governor of the RBI (2016–2018), succeeded by Shaktikanta Das as the 25th Governor.

• Agronomy: Precision and efficient irrigation (drip/sprinkler) combined with high-yielding seeds and balanced soil nutrition directly drives agricultural yield gains.

Correct Answer: Option (D) — To enhance rural income (also asset creation and livelihood security) • Welfare Economics: The primary objective of the Mahatma Gandhi National Rural Employment Guarantee Act (MGNREGA) is to enhance livelihood security and rural purchasing power by guaranteeing at least 100 days of wage employment in a financial year to every rural household whose adult members volunteer for unskilled manual work.

The Union Budget 2017-18 was built around the agenda 'TEC India' — to Transform, Energise, and Clean India; 'Educate India' was not one of the three stated pillars of the acronym.

The Green Revolution of the late 1960s is most accurately characterized as a package of 'Seed-Fertilizer-Water technology' because high-yielding variety (HYV) seeds required chemical fertilizers and assured irrigation together to succeed.

Amitabh Kant served as the Chief Executive Officer (CEO) of NITI Aayog from February 2016 to June 2022.

• Demographics (Census 2011): According to the 2011 Census, Bihar has the highest population density among all Indian states with 1,106 persons per square kilometre (surpassing West Bengal's 1,028).

• Demographics of Bihar: As per the 2011 Census of India, the overall sex ratio of Bihar is 918 females per 1,000 males (Gopalganj has highest at 1,021, Munger lowest at 876).

The Government of Bihar published its first ever 'Bihar Economic Survey' for the financial year 2006-07, tabled in the State Legislature in March 2007 by Deputy Chief Minister and Finance Minister Sushil Kumar Modi.

During the April–June 2018 quarter, the service sector accounted for the highest share of Foreign Direct Investment (FDI) equity inflows into Bihar.

According to the Bihar Economic Survey, more than 70% of Bihar's workforce is engaged in agriculture and allied activities for its livelihood.

According to the 12th Bihar Economic Survey (2017-18), Bihar's Gross State Domestic Product (GSDP) at constant (2011-12) prices grew at 10.3 percent during 2016-17.

Christian missionary proselytization, the General Service Enlistment Act (1856) requiring overseas travel by ship, and the withdrawal of foreign service allowance (Bhatta) directly provoked sepoy discontent, whereas 'inefficiency of the officers' was not a cause.

Correct Answer: Option (A) — Chandni Chowk to Palam • Mughal Decline: A popular contemporary Persian couplet satirized the diminished territorial writ of the later Mughals (Shah Alam II and Bahadur Shah Zafar): 'Saltanat-e-Shah Alam, Az Dilli ta Palam' (The realm of the Emperor extends only from Delhi/Chandni Chowk to Palam).

The Nizam of Hyderabad was the first Indian ruler to accept Lord Wellesley's Subsidiary Alliance in 1798 and remained consistently loyal to the British East India Company, whereas the Raja of Vizianagaram (1794), Poligars (1799–1805), and Velu Thampi (1808–09) revolted.

• Indigo Revolt 1859-60: The Neel Bidroha in Bengal broke out because European planters coerced ryots into signing exploitative contracts to cultivate unprofitable indigo instead of food crops at unremunerative fixed prices.

• Peasant Uprising: The Deccan Riots of May 1875 in Poona and Ahmednagar districts of Maharashtra were directed primarily against exploitative Gujarati and Marwari moneylenders (sahukars/mahajans) who charged exorbitant interest rates, manipulated debt bonds, and seized ancestral agricultural lands.

• Marxist Historiography: In his influential work 'India Today' (1940), Marxist historian Rajani Palme Dutt critically characterized the Indian National Congress as playing a dual role—both fighting against British imperialism and collaborating with it to protect bourgeois interests.

• Press History: 'The Times of India' (founded in 1838 as The Bombay Times) was an Anglo-Indian newspaper that generally supported British colonial administration and official policies, unlike nationalist publications like The Hindu, Bengalee, and The Mahratta.

Correct Answer: Option (D) — Atmaram Pandurang, Mohandas Karamchand Gandhi, Gopal Hari Deshmukh, Jyotiba Phule, Naoroji Furdonji • Social Reformers: Prarthana Samaj: Atmaram Pandurang; Young India: M.K. Gandhi; Lokhitvadi: Gopal Hari Deshmukh; Satyashodhak Samaj: Jyotirao Phule; Rehnumai Mazdayasan Sabha: Naoroji Furdonji.

• Nationalist Press: The Hindu was founded by G. Subramania Iyer; Kesari by Bal Gangadhar Tilak; The Bengalee by Surendranath Banerjee; Hindustani by Ganga Prasad Varma; Sudharak by Gopal Krishna Gokhale.

Following the assassination of Poona Plague Commissioner W. C. Rand by the Chapekar brothers in 1897, the British government prosecuted Tilak for sedition and sentenced him to 18 months' rigorous imprisonment, which earned him nationwide reverence and the title 'Lokmanya'.

Correct Answer: Option (B) — A little more than 21 years • Revolutionary History: Bhagat Singh was born in September 1907. When he and Batukeshwar Dutt threw non-lethal smoke bombs in the Central Legislative Assembly on 8 April 1929, he was 21 years and 6 months old (a little more than 21 years).

The Jallianwala Bagh Massacre occurred on 13 April 1919 in Amritsar during protests against the Rowlatt Act (Rowlatt Satyagraha) and the arrest of nationalist leaders Dr. Saifuddin Kitchlew and Dr. Satyapal.

Kunwar Singh took command of the rebel sepoys who marched from Danapur (Patna) to Arrah (Bhojpur) in July 1857 and besieged the British garrison at Arrah House.

• Tribal Revolts: The Chhotanagpur and Santhal Pargana regions of historical Bihar were the center of historic tribal uprisings including the Kol, Santhal, and Munda rebellions.

Dr. Sachchidananda Sinha critically remarked on colonial economic governance: 'So always with the assent and often to the dictates of the Chamber of Commerce, the Government of India is carried on, and this is the White Man's Burden.'

• Gandhian Movement: Mahatma Gandhi launched his first Satyagraha in India in 1917 in Champaran (Bihar) against the oppressive European indigo planters' tinkathia system, marking his successful entry into Indian freedom struggle.

During the Non-Cooperation Movement, anti-liquor picketing caused a steep drop in excise revenue, prompting the Government of Bihar and Orissa to circulate a list of famous figures (such as Alexander, Julius Caesar, Napoleon, and Shakespeare) who drank alcohol.

• Civil Disobedience in Bihar: Because Bihar is landlocked and lacked sea salt, the Salt Satyagraha quickly transformed into a powerful, widespread anti-Chowkidari tax refusal campaign led by local leaders in Saran, Champaran, and Bhagalpur.

• Constitutional Crisis 1938: The Congress Ministry in Bihar headed by Dr. Shri Krishna Sinha (and in UP under G.B. Pant) resigned on 15 February 1938 over the British Governor's refusal to release all political prisoners convicted during mass struggles.

Swami Sahajanand Saraswati (founder of the Bihar Provincial Kisan Sabha in 1929), Karyanand Sharma (leader of the Barahiya Tal Bakasht movement), Rahul Sankrityayan (Amwari Satyagraha), and Yadunandan Sharma (Reora Satyagraha) were all prominent leaders of the Bihar Kisan Sabha movement.

The length of the longest pole equals the space diagonal of the room: √(l² + b² + h²) = √(12² + 9² + 8²) = √(144 + 81 + 64) = √289 = 17 meters.

• Time and Distance Calculation:
• Total distance to cover = Length of train + Length of bridge = 150 m + 250 m = 400 meters.
• Speed = 144 km/hr = 144 (5 / 18) = 8 5 = 40 m/s.
• Time = Distance / Speed = 400 m / 40 m/s = 10 seconds.

Correct Answer: Option (B) — 15 • Number Theory: There are exactly 15 prime numbers between 1 and 50: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47.

Substituting x = -2/3 into 9x² – 3x – 11 gives 9(-2/3)² – 3(-2/3) – 11 = 9(4/9) + 2 – 11 = 4 + 2 – 11 = –5.

Percentage of candidates who took both subjects = (66% + 59%) – 100% = 25%. Therefore, the number of candidates who took both Hindi and History = 25% of 3000 = 0.25 × 3000 = 750.

• Step 1: Count decimal digits. Both numerator (0.00001225) and denominator (0.00005329) have exactly 8 decimal places. Thus, the decimal points cancel out:

(0.00001225) / (0.00005329) = (1225) / (5329) • Step 2: Compute square roots:

\sqrt{5329} = 73 \quad (73² = 5329) • Therefore:

From x + 1/y = 1, we get x = (y – 1)/y, so 1/x = y/(y – 1). From y + 1/z = 1, we get 1/z = 1 – y, so z = -1/(y – 1). Adding the two gives z + 1/x = -1/(y – 1) + y/(y – 1) = (y – 1)/(y – 1) = 1.

• Arithmetic Average: Total age of 4 sisters = 4 × 7 = 28 years. With mother included, number of persons = 5 and new average = 7 + 6 = 13 years. Total age = 5 × 13 = 65 years. Age of mother = 65 - 28 = 37 years.

Expressing 27 as 3³ gives 3^(x + 8) = (3³)^(2x + 1) = 3^(6x + 3). Equating the exponents gives x + 8 = 6x + 3, so 5x = 5 and x = 1.

S = ∑(n=1 to 10) 2n + ∑(n=1 to 10) (1/2) = 2 × [10 × 11 / 2] + 10 × (1/2) = 110 + 5 = 115.

• Acid-Base Chemistry: At 25 °C, pure neutral water and any neutral solution have a hydrogen ion concentration [H⁺] = 10⁻⁷ M, yielding a pH of -\log₁₀(10⁻⁷) = 7.

• Atomic Physics: The most abundant isotope of hydrogen, protium (¹₁H), consists of only 1 proton and 1 electron, possessing zero neutrons in its atomic nucleus (A = 1, Z = 1, N = A - Z = 0).

The angstrom (Å) is a unit of length used to measure electromagnetic wavelengths and atomic distances, where 1 Å = 10⁻¹⁰ meters.

• SI Units: In the International System of Units (SI), frequency (the number of periodic oscillations or cycles per second) is measured in hertz (Hz), named after the German physicist Heinrich Hertz.

• Molecular Biology: In 1953, James Watson and Francis Crick elucidated the double-helix structure of DNA at the Cavendish Laboratory, Cambridge, for which they were awarded the 1962 Nobel Prize in Physiology or Medicine (along with Maurice Wilkins).

A triglyceride is an ester derived from glycerol and three fatty acid molecules, constituting the main form of fat (lipid) stored in the human body and found in dietary oils and fats.

• Medical Diagnostics: An electroencephalogram (EEG) is a non-invasive test that records the electrical activity of the brain, widely used to detect seizures, epilepsy, head injuries, and sleep disorders.

The hypothalamus acts as the body's thermoregulatory center (thermostat), maintaining core human body temperature around 37°C (98.6°F).

In the visible spectrum (VIBGYOR), red light has the longest wavelength (~620–750 nm) and lowest frequency, whereas violet light has the shortest wavelength (~380–450 nm) and highest frequency.

• Temperature Formula: F = (C 9/5) + 32 -> F = (40 9/5) + 32 = (8 * 9) + 32 = 72 + 32 = 104 °F.

• Physics Units: In the SI system, electric power (P = V * I = W / t) is measured in watts (W), where 1 watt equals 1 joule per second. (Volt is potential, Ampere is current, Coulomb is charge).

An electric motor is an electromagnetic device that converts electrical energy into mechanical energy through the interaction of magnetic fields and current-carrying armature conductors.

• Human Physiology: Water makes up approximately 60% to 70% of an adult human's total body weight (with vital organs like brain, heart, and muscle having around 70%–75% water content).

• Electrical Instrumentation: An ammeter (ampere meter) is the instrument connected in series in an electric circuit to measure the magnitude of electric current in amperes. A voltmeter measures voltage, and a potentiometer measures EMF.

• Environmental Science: Carbon dioxide (CO2) accounts for approximately 76% of all anthropogenic greenhouse gas emissions, making it the principal driver of global warming among options.

• Nobel Citation: Albert Einstein was awarded the 1921 Nobel Prize in Physics (awarded in 1922) 'for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect', demonstrating that light consists of discrete energy packets (photons).

• Cell Biology: The mitochondrion is designated as the 'powerhouse of the cell' because it generates over 90% of the cell's biochemical energy supply through cellular respiration and oxidative phosphorylation in the form of ATP (adenosine triphosphate).

Acquired Immunodeficiency Syndrome (AIDS) is caused by the Human Immunodeficiency Virus (HIV), a retrovirus that attacks the body's CD4+ T-lymphocyte immune cells.

A hygrometer is used to measure the relative humidity (water vapour content) of the atmosphere, whereas a hydrometer measures the relative density of liquids.

Pressure is defined as force per unit area (P = F/A), so its SI unit is Newton per square meter (N/m²), also called the Pascal (Pa).