The outermost layer of the skin is called the: MCQ with Answer and Explanation

Explanation:
Pellagra is caused by a severe deficiency of Vitamin B3 (Niacin) or its precursor, the amino acid tryptophan. The classic symptoms are the '4 Ds': dermatitis (symmetrical, pigmented rash on sun-exposed skin), diarrhea, dementia (neurological symptoms), and eventually death if untreated. It is historically associated with diets heavily reliant on untreated corn (maize), which has low bioavailable niacin and tryptophan.

Explanation:
Kala-azar (visceral leishmaniasis) is caused by the protozoan Leishmania donovani, transmitted by sandfly bite. Tetanus is bacterial (Clostridium tetani), tuberculosis bacterial (Mycobacterium tuberculosis), measles viral. Protozoan diseases include malaria, amoebiasis, sleeping sickness, giardiasis. Kala-azar causes fever, weight loss, splenomegaly, and is endemic in parts of India.

Explanation:
The bicuspid valve (mitral valve) has two cusps and is located between the left atrium and left ventricle, preventing backflow during ventricular systole. The tricuspid valve is on the right side. Semilunar valves are at the exits of the aorta and pulmonary artery. Mitral valve prolapse is a common condition.