PINAKA is an indigenously developed Multi Barrel Rocket Launch (MBRL) system designed and produced by the Defence Research and Development Organisation (DRDO) of India. It is capable of firing a salvo of rockets to deliver explosive warheads over large areas with high accuracy. Pinaka is primarily used by the Indian Army for long-range artillery support and has a range of up to 75 km in its upgraded version (Pinaka Mk-II).

Other options (for context)

• Anti-submarine torpedo and research vehicle: Refers to underwater weapon systems, not related to Pinaka.
• Aircraft carrier: A large naval vessel capable of carrying aircraft; Pinaka is not a ship.
• Guided missile frigate submarine warship: Refers to naval warships, not a land-based rocket launcher.

Explanation: The ozone layer is located in the stratosphere, which is the second layer of the Earth’s atmosphere, lying above the troposphere and extending from about 10 km to 50 km above the Earth’s surface. The ozone layer contains a high concentration of ozone gas (O₃), which absorbs most of the Sun’s harmful ultraviolet (UV) radiation. This protective shield prevents genetic damage, skin cancer, and other harmful effects on living organisms.

A Lunar Eclipse occurs when the Earth comes between the Sun and the Moon, causing the Earth’s shadow to fall on the Moon. This alignment blocks the sunlight that normally reflects off the Moon’s surface, making it appear dark or reddish (known as a Blood Moon). Lunar eclipses only occur during a full moon when the Sun, Earth, and Moon are in a straight line (or nearly so).

Other options (for context)

• When Sun is between Earth and Moon: Incorrect — this alignment causes no eclipse.
• When Moon is between Earth and Sun: This alignment causes a solar eclipse, not a lunar one.
• When Earth is between Sun and other celestial bodies: Too general — lunar eclipse specifically involves the Moon.

Explanation: The blue whale (Balaenoptera musculus) holds the record as the largest mammal and the largest living organism on Earth. Adult blue whales can reach lengths of up to 30 meters (98 feet) and weigh over 180 tons. Despite their size, they feed mainly on small shrimp-like creatures called krill, filtering them through their baleen plates. Whales are warm-blooded, breathe air through blowholes, and give birth to live young — all key mammalian traits.

Comparison:

• Blue whale (largest mammal): up to 30 m long, ~180 tons
• African elephant (largest land mammal): up to 4 m tall, ~6 tons
• Rhinoceros: up to 2 m tall, ~2 tons

Explanation: An artery is a large blood vessel that carries blood away from the heart to various parts of the body. Arteries have thick, elastic walls to withstand high pressure. In contrast, veins carry blood toward the heart, and capillaries are tiny vessels that connect arteries and veins.

The O blood group, specifically O negative (O−), is considered the Universal Donor because it can be safely transfused to people of all other blood groups. This is due to the absence of A and B antigens on red blood cells, minimizing the risk of immune reactions during transfusion.

• A: Can donate only to A and AB groups.
• AB: Universal recipient, not donor.
• B: Can donate only to B and AB groups.

Explanation: The S.I. unit of electric current is the Ampere (A). It is defined as the rate of flow of electric charge through a conductor. One ampere equals one coulomb of charge passing through a point in one second.

Explanation: Nucleons are the particles that make up the nucleus of an atom — namely, protons and neutrons. A positron is not a nucleon; it is the antiparticle of the electron, having the same mass as an electron but a positive charge, and exists outside the nucleus.