Explanation: In humans, the spinal cord gives rise to 31 pairs of spinal nerves. Each spinal nerve is a mixed nerve containing both sensory and motor fibers. They are divided into groups based on the region of the vertebral column from which they originate:

• 8 pairs — Cervical nerves
• 12 pairs — Thoracic nerves
• 5 pairs — Lumbar nerves
• 5 pairs — Sacral nerves
• 1 pair — Coccygeal nerve

These spinal nerves connect the central nervous system (CNS) to different parts of the body, transmitting sensory information to the brain and motor commands to muscles.

The Exosphere is the uppermost layer of the Earth's atmosphere. It lies above the thermosphere and gradually merges into outer space. The exosphere extends roughly from 700 km to 10,000 km above the Earth's surface. In this layer, air is extremely thin, and gas molecules such as hydrogen and helium are sparse and can even escape into space.

Other options (for context)

• Stratosphere: Second layer from the Earth’s surface; contains the ozone layer.
• Mesosphere: Lies above the stratosphere; meteors burn up here.
• Ionosphere: A region within the thermosphere important for radio communication, not the outermost layer.

Explanation: Vitamins are classified into two categories based on their solubility — fat-soluble and water-soluble. Vitamin C (ascorbic acid) and the B-complex vitamins are water-soluble, meaning they dissolve in water and are not stored in the body. Therefore, they must be consumed regularly through diet. Deficiency of Vitamin C causes scurvy, characterized by bleeding gums and delayed wound healing.

Explanation: Trichology is derived from the Greek word “trikhos”, meaning hair. It is a specialized field within dermatology that focuses on the structure, function, and diseases of hair and scalp. Trichologists diagnose and treat conditions such as hair loss (alopecia), dandruff, scalp infections, and hair shaft disorders.

Common Hair Disorders Studied in Trichology:

• Alopecia: Hair loss due to genetics, stress, or autoimmune disorders.
• Dandruff (Seborrheic dermatitis): Scalp condition causing flaking and itching.
• Tinea capitis: Fungal infection of the scalp (ringworm).

Explanation: Wind energy is a clean and renewable source of energy that does not cause environmental pollution. It is generated by converting the kinetic energy of moving air into mechanical or electrical energy using wind turbines. Unlike fossil fuels such as coal or mineral oil, wind energy does not release carbon dioxide, sulfur dioxide, or other greenhouse gases. It is, therefore, a pollution-free and sustainable source of power, widely used for electricity generation in wind farms.

Explanation: The scientific name of Vitamin C is Ascorbic Acid. It is a water-soluble vitamin essential for the growth, repair, and maintenance of body tissues. Vitamin C acts as a powerful antioxidant and helps in the synthesis of collagen, absorption of iron, and boosting the immune system. A deficiency of Vitamin C leads to the disease Scurvy, characterized by bleeding gums, weakness, and delayed wound healing. Natural sources include citrus fruits like oranges, lemons, amla, and guava.

Explanation: The pituitary gland is a small, pea-sized endocrine gland located at the base of the brain, just beneath the hypothalamus. It is often called the "master gland" because it secretes several hormones (like growth hormone, TSH, FSH, LH, and prolactin) that control other endocrine glands and various physiological processes.

Explanation: ROM (Read Only Memory) retains its data even when the power is turned off, making it non-volatile memory. It stores essential programs such as the computer’s firmware or BIOS, which are required for booting the system. In contrast, RAM loses all information when power is shut down.

Explanation: A lens is generally made of flint glass, which contains lead oxide. Flint glass has a higher refractive index than ordinary glass, allowing it to bend light more effectively. This property makes it ideal for manufacturing optical instruments such as lenses and prisms.