Explanation: The nerve cell or neuron is the longest cell in animals. It consists of a cell body, dendrites, and a long fiber called the axon. In humans, the axon of a motor neuron can be over 1 meter long (from the spinal cord to the toes). This structure helps transmit electrical impulses rapidly across the body, allowing coordination and communication between organs.

The Green Revolution is associated with Agriculture. It refers to the period during the 1960s–70s when new technologies like high-yield variety (HYV) seeds, fertilizers, irrigation, and pesticides were introduced to boost food grain production, especially wheat and rice. It helped India achieve self-sufficiency in food production.

• Sericulture: Rearing of silkworms for silk.
• Fishery: Cultivation and harvesting of fish.
• Cultivation of bees: Known as apiculture, for honey production.

Explanation: The habitat of an organism is its natural living place where it finds food, water, shelter, and mates for reproduction. Examples include a pond for a frog, soil for an earthworm, and forest for a tiger. Each species has a specific habitat suited to its survival needs. The niche, on the other hand, describes the organism’s role or function in that habitat, such as how it obtains food or interacts with others.

Explanation: White blood cells (WBCs), also known as leukocytes, are responsible for producing the immune response in the human body. They defend against infections by attacking bacteria, viruses, and other foreign invaders, helping to maintain the body’s immunity.

Explanation: Proteins are complex organic compounds composed of smaller units called amino acids. Each amino acid contains an amino group (–NH₂), which contributes nitrogen to the molecular structure. This makes nitrogen an essential element in all proteins. Carbohydrates and fats lack nitrogen, while only some vitamins contain it.

Ocean Thermal Energy (OTE) is produced due to the temperature difference at different levels in the ocean. The surface water is warmer because it absorbs sunlight, while the deeper layers remain cold. This temperature gradient is used to run a heat engine that generates electricity — a process known as Ocean Thermal Energy Conversion (OTEC).

• Tides: Related to gravitational pull, not temperature.
• Pressure difference: Exists but not used for energy generation.
• Waves: Used in wave energy systems, not OTEC.

Explanation: Sugarcane (Saccharum officinarum) is a tall, jointed, perennial grass belonging to the family Poaceae. It has thick stems rich in sucrose, which is extracted to produce sugar. The plant reproduces mainly through stem cuttings (vegetative propagation). Its structure and growth habit are similar to other grasses like maize and bamboo.

Explanation: Cerebral malaria is a severe neurological complication of malaria infection caused by Plasmodium falciparum. The parasite infects red blood cells, making them sticky and causing them to block small blood vessels in the brain. This leads to high fever, seizures, coma, and can be fatal if untreated. Transmission occurs through the bite of an infected female Anopheles mosquito.

Explanation: Inside a sealed pressure cooker, the pressure is higher than atmospheric pressure, which raises the boiling point of water to about 121℃. This allows food to cook faster because water and steam reach higher temperatures than at normal atmospheric pressure.