The glomerulus is a cluster of: MCQ with Answer and Explanation

Explanation:
The loop of Henle, especially the descending limb (permeable to water) and ascending limb (impermeable, active salt transport), creates an osmotic gradient in the medulla. This countercurrent multiplier system enables the kidney to produce concentrated or dilute urine depending on hydration status. ADH acts on the collecting duct to utilize this gradient.

Explanation:
Matthew Meselson and Franklin Stahl, in 1958, used density gradient centrifugation of E. coli grown in N¹⁵ medium to prove that DNA replication is semi-conservative: each new DNA molecule consists of one old and one new strand. Watson and Crick proposed the double helix, Hershey-Chase confirmed DNA as genetic material, Chargaff formulated base pair rules.

Explanation:
Photosystem II (PSII), also known as P680, is the first photosystem in the non-cyclic electron transport pathway (Z-scheme). It is responsible for the photolysis of water, a process where water molecules are split into oxygen, protons (H+), and electrons. This oxygen is released as a byproduct of photosynthesis.