The vitamin that is a component of the visual pigments in the retina is: MCQ with Answer and Explanation

Explanation:
Aldosterone, secreted by the adrenal cortex, increases sodium reabsorption (and water follows) and potassium secretion in the distal tubule and collecting duct. ADH increases water reabsorption only. Renin is an enzyme, natriuretic peptides inhibit sodium reabsorption.

Explanation:
CCK, released from the duodenum in response to fats, stimulates contraction of the gall bladder and release of bile, and also stimulates pancreatic enzyme secretion. Gastrin stimulates HCl, secretin bicarbonate, motilin GI motility.

Explanation:
In C4 plants like maize and sugarcane, CO₂ is initially fixed in mesophyll cells by PEP carboxylase, producing a four-carbon compound oxaloacetic acid (OAA), which is then converted to malate or aspartate and transported to bundle sheath cells. Here, CO₂ is released and enters the Calvin cycle. This adaptation minimizes photorespiration.