Which ion is essential for the blood clotting process? MCQ with Answer and Explanation

Explanation:
Kwashiorkor is a severe form of malnutrition in children caused by a significant deficiency of protein in the diet, despite potentially adequate calorie intake. It is characterized by edema (swelling, especially in the belly due to low albumin), an enlarged liver, thinning hair, and a 'flaky paint' skin rash. Marasmus is caused by overall protein-calorie deficiency.

Explanation:
The tracheal wall contains C-shaped hyaline cartilage rings that keep the airway open, preventing collapse due to negative pressure during inspiration. Smooth muscle and fibrous tissue connect the rings, ciliated epithelium sweeps mucus upward.

Explanation:
Melatonin, synthesized from serotonin, is released in darkness, regulating circadian rhythms and promoting sleep. Serotonin is a neurotransmitter, dopamine reward, acetylcholine muscle contraction.