Explanation: Opium is obtained from the latex present in the unripe capsule of the poppy plant (Papaver somniferum). The latex is collected by making incisions on the capsule, and after drying, it forms raw opium, which contains alkaloids like morphine and codeine.

Sound waves from a loudspeaker are produced by vibrations of its diaphragm. When an electric current passes through the speaker coil, it causes the diaphragm to move back and forth, creating compressions and rarefactions in the air. These pressure variations travel as sound waves to our ears.

• Frequency: Determines pitch but does not create sound.
• Pitch: A property of sound, not its cause.
• Amplitude: Determines loudness but not the origin of sound.

Sericulture is the rearing and cultivation of silkworms for the production of silk. The process involves raising silkworms on mulberry leaves, harvesting their cocoons, and then extracting silk fibers from these cocoons. The most commonly used silkworm species is Bombyx mori. Sericulture is an important cottage industry in countries like India, China, and Japan.

Other options (for context)

• Fishes: Their rearing is called Pisciculture.
• Honey bees: Their rearing is called Apiculture.
• Earth worms: Their cultivation for composting is called Vermiculture.

Tuberculosis (TB) is commonly known as the "White Plague". It earned this name because it causes extreme paleness and weight loss in affected individuals. Tuberculosis is an infectious disease caused by the bacterium Mycobacterium tuberculosis, primarily affecting the lungs but can also spread to other parts of the body. It spreads through airborne droplets when an infected person coughs or sneezes.

Other options (for context)

• Typhoid: Caused by Salmonella typhi, affects the intestine and causes high fever.
• Malaria: Caused by Plasmodium parasite transmitted through mosquito bites.
• Plague: Caused by Yersinia pestis, historically known as the “Black Death,” not the white plague.

Explanation: Coriander (Coriandrum sativum) is a herb belonging to the family Apiaceae. The leaves are used as a fresh herb (commonly known as cilantro), and the dried fruits (often referred to as coriander seeds) are used as a spice. The fruits contain essential oils like linalool and borneol, which give coriander its characteristic aroma and flavor.

Uses:

• Leaves — used in cooking for flavoring and garnishing dishes.
• Dried fruits (seeds) — used as a spice, in curry powders, and for medicinal purposes (digestive aid).

Velocity is a vector quantity because it has both magnitude and direction. It represents the rate of change of displacement of an object. Unlike speed, which only tells how fast an object is moving, velocity also indicates the direction of motion.

Other options (for context)

• Mass: A scalar quantity — it has magnitude only, no direction.
• Volume: Scalar — represents space occupied by matter, without direction.
• Speed: Scalar — measures how fast an object moves but not in which direction.

Helium is used instead of nitrogen in the breathing mixture for deep-sea divers. At high pressures underwater, nitrogen can dissolve in blood and cause nitrogen narcosis or “rapture of the deep.” Helium, being inert and less soluble in blood, prevents this condition and makes breathing easier under pressure.

• Argon, Xenon, Krypton: Inert gases but not suitable due to higher density and narcotic effects.

In organic farming, chemical fertilizers are not used. Instead, farmers rely on natural manures, compost, and biofertilizers to enrich the soil. Organic farming avoids synthetic pesticides and focuses on maintaining ecological balance, soil fertility, and sustainable crop production.

• Intercropping: Often used to increase productivity naturally.
• Manures: Essential in organic farming for soil health.
• Biofertilizers: Widely used to promote natural nutrient availability.