The organ that filters blood, removes old RBCs, and stores platelets is the: MCQ with Answer and Explanation

Explanation:
Cholera, caused by Vibrio cholerae, produces cholera toxin that stimulates massive secretion of water and electrolytes into the intestinal lumen, leading to profuse, watery diarrhea resembling rice water, causing rapid dehydration. Treatment is oral rehydration therapy and antibiotics. Typhoid causes fever, dysentery causes bloody stools.

Explanation:
Vitamin B₁₂ (cobalamin) is required for DNA synthesis and RBC maturation. Deficiency causes pernicious anemia. It also maintains myelin sheath.

Explanation:
John Gibbon developed the heart-lung machine and performed the first successful open-heart surgery using it in 1953. Barnard did first heart transplant.