Riboflavin is also known as: MCQ with Answer and Explanation

Explanation:
Cerebrospinal Fluid (CSF) is a clear, watery fluid that circulates through the ventricles of the brain, the central canal of the spinal cord, and the subarachnoid space. It provides mechanical protection (cushioning), chemical stability, and waste removal for the central nervous system. CSF is primarily produced by the choroid plexus, which is a network of highly vascularized, specialized ependymal cells located within the ventricles of the brain (lateral, third, and fourth ventricles).

Explanation:
Light reactions occur in thylakoid membranes, producing ATP, NADPH, and oxygen. Oxygen comes from water (photolysis), not CO₂. So statement 2 is incorrect. 1 and 3 are correct.

Explanation:
Parietal (oxyntic) cells in the gastric glands of the stomach secrete hydrochloric acid (HCl), which activates pepsinogen to pepsin, kills bacteria, and provides an acidic pH (1.5-2.0) for protein digestion. Liver produces bile, pancreas secretes digestive enzymes and bicarbonate, goblet cells secrete mucus. Intrinsic factor, required for vitamin B₁₂ absorption, is also secreted by parietal cells.