The element that is a key component of the thyroid hormones T₃ and T₄ is: MCQ with Answer and Explanation

Explanation:
Cholera, caused by Vibrio cholerae, is transmitted through contaminated water and food. Malaria is vector-borne, TB airborne, rabies through animal bite.

Explanation:
Lamarck proposed that organs used extensively develop and those not used degenerate, and these acquired traits are inherited (inheritance of acquired characters). Darwin's theory is natural selection, Wallace independently proposed natural selection, Weismann disproved Lamarckism.

Explanation:
Vitamin K is essential for the synthesis of clotting factors (II, VII, IX, X) in the liver. Deficiency leads to prolonged clotting time and excessive bleeding. Vitamin A is for vision, C for collagen (scurvy causes bleeding gums but not clotting defect), D for bones. Newborns receive vitamin K injection to prevent hemorrhagic disease. Green leafy vegetables are rich sources.