The functional unit of the kidney is: MCQ with Answer and Explanation

Explanation:
Sewage contains organic matter that can be broken down by microorganisms, hence biodegradable. DDT, plastics, and mercury are non-biodegradable, persisting in the environment and accumulating in food chains (biomagnification). Biodegradable pollutants can be decomposed naturally, reducing long-term harm, but excessive loads can cause eutrophication. Non-biodegradable pollutants require special disposal and cause lasting ecological damage.

Explanation:
Vitamin K is a cofactor for γ-glutamyl carboxylase, which modifies glutamate residues in clotting factors, enabling calcium binding and coagulation.

Explanation:
Insulin, from beta cells, lowers blood glucose by stimulating glucose uptake into muscle and adipose tissue (via GLUT4) and promoting glycogenesis. Glucagon, cortisol, and GH raise blood glucose. Insulin is the only hormone that significantly lowers blood glucose.