The scientist who discovered the bacterium that causes plague (Yersinia pestis) was: MCQ with Answer and Explanation

Explanation:
The Loop of Henle is a U-shaped tube extending into the renal medulla. Its primary function is to concentrate the urine by creating a hyperosmotic gradient in the medullary interstitium through the counter-current multiplier mechanism. The descending limb is permeable to water but not salts, while the ascending limb is impermeable to water but actively transports salts out. This gradient allows the collecting duct to reabsorb water under the influence of ADH.

Explanation:
All are correct: biodiversity has three levels; hotspots have high endemism and threat; Western Ghats is a recognized hotspot.

Explanation:
During intense exercise, when oxygen supply is insufficient, muscle cells switch to anaerobic glycolysis, producing ATP and lactic acid from glucose. Lactic acid accumulation lowers pH, causing muscle fatigue, soreness, and cramps. It is later converted back to glucose in the liver (Cori cycle). Ethanol is produced by yeast fermentation.