Previous Year UPSC Questions

Explanation

Reproduction is the process by which organisms produce offspring. It ensures the continuation of a species. There are two main modes of reproduction:

Asexual Reproduction involves a single parent and produces offspring that are genetically identical to the parent. Examples include binary fission (in bacteria), budding (in yeast), and parthenogenesis (in some insects). Sexual Reproduction involves two parents (usually of different sexes) and combines genetic material from both parents to create offspring with unique genetic variations. Examples include fertilization in animals and pollination in plants. Assertion A is True: Amoeba, a unicellular protozoan reproduces asexually through binary fission, a process where the parent cell divides into two genetically identical daughter cells. Process of Binary Fission in Amoeba:

Growth Phase: The Amoeba increases in size, accumulating nutrients required for division. Nuclear Division (Mitosis): The nucleus undergoes mitotic division, ensuring that both daughter cells receive an identical set of genetic material. Cytoplasmic Division: The cytoplasm divides, creating two separate daughter cells. Formation of Two New Amoebae: Each daughter cell becomes independent and grows into a mature Amoeba. Reason R is True: Asexual reproduction is common among single-celled organisms, and in plants and animals with relatively simple organisations. Reason R is the correct explanation of Assertion A, since, Amoeba is a unicellular organism and all unicellular organisms reproduce asexually. (Note: Some unicellular organisms are capable of sexual reproduction, such as conjugation in ciliates like Paramecium, where two cells exchange genetic material. Additionally, some unicellular fungi, like yeasts, can undergo both asexual reproduction (such as budding) and sexual reproduction (like mating and meiosis) Fig.: Binary fission in Amoeba

Explanation

Assertion (A) is true: Diabetes insipidus(DI) is a condition characterized by the inability to properly regulate water balance in the body. It leads to excessive urination (polyuria) and dehydration. As a result, individuals with DI often experience intense thirst (polydipsia) to compensate for the excessive water loss. Reason (R) is false: Diabetes insipidus is caused by either insufficient secretion of vasopressin (antidiuretic hormone) or the kidneys’ inability to respond to vasopressin. Excess secretion of vasopressin is not associated with DI. Excess secretion of vasopressin would lead to water retention, not excessive thirst. Thus, the Assertion A is true but the Reason R is false.

Explanation

Workers in the coal mining industry are most affected by pneumoconiosis. Pneumoconiosis is a lung disease caused by the inhalation of dust, particularly mineral or industrial dust over a prolonged period. It primarily affects workers in industries where they are exposed to high levels of airborn e particles. Coal workers’ pneumoconiosis (CWP), also known as black lung disease, is caused by prolonged inhalation of coal dust, making coal miners the most affected group. Other forms of pneumoconiosis include silicosis (caused by silica dust, affecting quarry and glass industry workers) and asbestosis (caused by asbestos exposure).

Explanation

The Balearic Islands are an archipelago located in the western Mediterranean Sea, near the eastern coast of Spain. They are a popular tourist destination known for their scenic landscapes, beaches, and cultural heritage. They are an autonomous community of Spain and consist of four main islands.

Explanation

Pair (a) is correctly matched: Nassau is the capital city of The Bahamas and its largest city. It is located on New Providence Island and is a major tourist hub. Pair (b) is correctly matched: San José is the capital and largest city of Costa Rica. It is the political, economic, and cultural center of the country. Pair (c) is incorrectly matched: Belmopan is actually the capital of Belize, not Nicaragua. The correct capital of Nicaragua is Managua. Pair (d) is correctly matched: Santo Domingo is the capital and largest city of the Dominican Republic. It is one of the old-est European settlements in the Americas, founded in 1496.

Explanation

Option (d) is correct: Mount St. Helens is in Washington State, USA, within the Pacific Ring of Fire. Mount St. Helens is an active stratovolcano located in Washington State, USA. It is part of the Cascade Range and is known for its catastrophic eruption on May 18, 1980, which was one of the most destructive volcanic events in U.S. history. Options (a), (b) and (c) are incorrect:

Chile has several active volcanoes, including Villarrica and Llaima. Japan has famous volcanic mountains like Mount Fuji and Sakurajima. The Philippines has Mount Pinatubo and Mayon Volcano.

Explanation

Option (b) is correct: Lithuania is a Baltic country in Northern Europe. It shares land borders with Latvia to the north, Belarus to the east and south, Poland to the south, and Russia (Kaliningrad) to the west. Ukraine does not share a border with Lithuania. Belarus lies between them.

Explanation

Peshawar, the capital of Khyber Pakhtunkhwa province, is the northernmost among these cities. Moving southward, Islamabad, the capital of Pakistan, comes next. Further south lies Gujranwala, a major industrial city in Punjab province. Finally, Multan, known for its Sufi shrines, is located in southern Punjab, making it the southernmost in the given options. Therefore, the correct north-to-south order is Peshawar Islamabad Gujranwala Multan.

Explanation

The cities and their respective rivers are: A-4; B-3; C-2; D-1 A is correctly matched with 4: The Potomac River, flowing through the eastern United States, serves as a boundary between Maryland and Virginia and passes through notable cities like Washington, D.C., Alexandria, and Harpers Ferry. B is correctly matched with 3: The Spree River, a tributary of the Havel River, flows through Berlin and is central to the city’s waterways, connecting it to other regions like Cottbus and Spandau. C is correctly matched with 2: The Seine River is one of France’s major rivers, flowing through Paris and other cities like Rouen and Le Havre. It is famous for its iconic landmarks along its banks in Paris, including the Eiffel Tower and numerous historic bridges. D is correctly matched with 1: The Manzanares River, though relatively small, flows through Madrid and plays an important role in local recreation and urban development. Each of these rivers holds cultural, historical, or economic significance for their respective cities.

Explanation

Statement 1 is incorrect: Great Britain consists of England, Scotland, and Wales. It does not include Northern Ireland. The United Kingdom (UK) comprises Great Britain and Northern Ireland.

Statement 2 is correct: England covers approximately 53% of the total area of the UK (130,279 km2 out of 242,495 km2), making the statement accurate.