The valve between the right atrium and right ventricle is the: MCQ with Answer and Explanation

Explanation:
Pellagra, with the 3 Ds (dermatitis, diarrhea, dementia), is due to deficiency of niacin (vitamin B₃) or tryptophan. Beriberi is B₁, scurvy C, rickets D. Niacin is part of NAD and NADP.

Explanation:
Vitamin D (cholecalciferol) is unique as it can be synthesized in the skin from 7-dehydrocholesterol in the presence of UV-B radiation. It acts as a hormone to regulate calcium and phosphate homeostasis. It must be activated in the liver and kidneys. It is also obtained from dietary sources like fatty fish, egg yolk. Deficiency causes rickets/osteomalacia.

Explanation:
Ringworm (dermatophytosis) is a superficial fungal infection of the skin, hair, or nails. It is caused by dermatophyte fungi, primarily from the genera Microsporum, Trichophyton, and Epidermophyton. Despite the name, it is not caused by a worm. Aspergillus can cause aspergillosis, and Saccharomyces is yeast used in baking and brewing.