Which pathogen causes tuberculosis in humans? MCQ with Answer and Explanation

Explanation:
The sinoatrial node spontaneously depolarizes, setting the rhythm of the heart. The reason correctly explains its role as pacemaker.

Explanation:
A point mutation is a genetic mutation where a single nucleotide base is changed, inserted, or deleted from a sequence of DNA or RNA. The classic example is sickle cell anemia, caused by a single point mutation in the beta-globin gene, where adenine is replaced by thymine, changing the amino acid from glutamic acid to valine.

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.