In the human respiratory system, the 'Surfactant' is a lipoprotein complex secreted by which cells to reduce surface tension in the alveoli? MCQ with Answer and Explanation

Explanation:
Pellagra, characterized by dermatitis, diarrhea, and dementia (3 Ds), is caused by a deficiency of niacin (vitamin B₃) or its precursor tryptophan. It is common in populations with corn-based diets lacking tryptophan. Beriberi is due to B₁ deficiency, cheilosis to B₂, peripheral neuropathy to B₆. Niacin is a component of coenzymes NAD and NADP.

Explanation:
The sporozoite is the motile infective stage injected by the female Anopheles mosquito into the human host. It invades liver cells. Gametocytes are the stage taken up by the mosquito, merozoites are released from liver and infect RBCs.

Explanation:
Erythroblastosis fetalis (hemolytic disease of the newborn) is primarily caused by Rh incompatibility. It occurs when an Rh-negative mother carries an Rh-positive fetus. During the first pregnancy, fetal Rh+ red blood cells may enter the mother's circulation, prompting her to produce anti-Rh antibodies. In subsequent pregnancies with an Rh+ fetus, these antibodies cross the placenta and destroy the fetal red blood cells, causing severe anemia and jaundice.