Explanation: Animals that live in or on trees are called arboreal animals. They are adapted to climbing and moving about among branches. Examples include monkeys, squirrels, chameleons, and tree frogs. Their adaptations may include grasping limbs, prehensile tails, claws, or adhesive pads that help them cling to tree surfaces and move efficiently among branches.

Explanation: Dakshin Gangotri is India’s first scientific research station established in Antarctica in 1983–84. It was set up by the Indian Antarctic Programme under the National Centre for Polar and Ocean Research (NCPOR). Located about 2,500 km from the South Pole, it served as a base for scientific studies related to glaciology, meteorology, and environmental sciences. Though it is now buried under ice and functions as a supply base, it marked India’s permanent presence in Antarctica. Later stations include Maitri (1989) and Bharati (2012).

Explanation: CNG stands for Compressed Natural Gas. It is an eco-friendly fuel made primarily of methane (CH₄) and is used as an alternative to petrol and diesel. CNG burns cleanly, producing fewer pollutants and helping reduce air pollution.

Vitamin-B complex and Vitamin-C are water-soluble vitamins. This means they dissolve easily in water and are not stored in the body; hence, they must be consumed regularly through diet. Excess amounts of these vitamins are excreted through urine. Vitamin-B complex includes B₁ (Thiamine), B₂ (Riboflavin), B₃ (Niacin), B₆, B₁₂, and others that play key roles in metabolism and energy production. Vitamin-C (Ascorbic acid) helps in collagen formation, boosts immunity, and acts as an antioxidant.

Other options (for context)

• Vitamin-A & Vitamin-B: Vitamin-A is fat-soluble, while Vitamin-B is water-soluble.
• Vitamin-C & Vitamin-D: Vitamin-C is water-soluble, but Vitamin-D is fat-soluble.
• Vitamin-A & Vitamin-K: Both are fat-soluble vitamins.

Diseases like Polio and Chicken Pox are caused by viruses. The Polio virus attacks the nervous system and can lead to paralysis, while the Varicella-zoster virus causes Chicken Pox, characterized by itchy blisters and fever. Viruses are acellular infectious agents that can reproduce only inside the living cells of a host organism.

Other options (for context)

• Bacteria: Cause diseases like tuberculosis, cholera, and typhoid, not polio or chicken pox.
• Protozoa: Cause diseases such as malaria and amoebiasis.
• Algae: Generally non-pathogenic; they do not cause human diseases like polio or chicken pox.

Explanation: A carnivore is an animal that primarily eats the flesh of other animals. The tiger (Panthera tigris) is a true carnivore and an apex predator in its ecosystem. It has sharp canines and retractable claws adapted for hunting and tearing flesh. Tigers play a vital role in maintaining the ecological balance by controlling herbivore populations in forests.

Explanation: The Olive Ridley turtle (Lepidochelys olivacea) is the smallest and most abundant species of sea turtle found primarily in warm and tropical waters, including the Indian Ocean. It is named for the olive color of its shell. These turtles are famous for their unique mass nesting phenomenon known as “arribada”, where thousands of females come ashore simultaneously to lay eggs. In India, large nesting sites are found along the coast of Odisha, especially at Gahirmatha Beach and the Rushikulya River mouth.

Explanation: A barometer is an instrument used primarily for measuring atmospheric pressure. It helps in weather forecasting and determining altitudes (since atmospheric pressure decreases with height). A mercury barometer consists of a glass tube filled with mercury inverted in a mercury reservoir. When air pressure changes, the height of the mercury column changes accordingly. However, a barometer cannot measure the density of a liquid — that function is performed by a hydrometer.