Which part of the brain controls breathing and heart rate? MCQ with Answer and Explanation

Explanation:
Vitamin C, chemically ascorbic acid, is a water-soluble vitamin essential for collagen synthesis, wound healing, iron absorption, and antioxidant function. Its deficiency causes scurvy (bleeding gums, weakness). Vitamin A is retinol, B₁ is thiamine, D is calciferol. Vitamin C is abundant in citrus fruits, guava, amla. It is heat-labile and easily destroyed by cooking.

Explanation:
Abscission is the natural shedding of plant parts. It is primarily promoted by ethylene and abscisic acid (ABA), which stimulate the formation of an abscission zone at the base of the petiole or pedicel. This zone consists of weak-walled cells that break down, causing the part to fall. Auxin, conversely, delays abscission. Exam tip: Ethylene is the 'ripening and shedding' hormone.

Explanation:
Thyroxine (T4) and Triiodothyronine (T3) are the main hormones secreted by the thyroid gland. They play a crucial role in regulating the basal metabolic rate (BMR), which is the rate at which the body uses energy at rest. They also influence growth, development, and body temperature. Calcitonin, also from the thyroid, regulates blood calcium.