The element that is a component of the vitamin B₁₂ molecule is: MCQ with Answer and Explanation

Explanation:
The dermis, lying beneath the epidermis, is a connective tissue layer containing collagen and elastin fibers, blood vessels, nerve endings, sweat glands, hair follicles, and sebaceous glands. The epidermis is the outermost protective layer, the hypodermis is subcutaneous fat, and the stratum corneum is the outermost part of the epidermis.

Explanation:
Cholera, caused by Vibrio cholerae, produces cholera toxin that stimulates massive secretion of water and electrolytes into the intestinal lumen, leading to profuse, watery diarrhea resembling rice water, causing rapid dehydration. Treatment is oral rehydration therapy and antibiotics. Typhoid causes fever, dysentery causes bloody stools.

Explanation:
The oblique entry of the ureters into the bladder creates a valve-like effect, preventing reflux. The urethral sphincter controls urination.