Assertion (A): Fermentation produces less ATP than aerobic respiration. Reason (R): Fermentation involves only glycolysis and does not use the Krebs cycle or electron transport chain. MCQ with Answer and Explanation

Explanation:
Angiosperms are flowering plants where seeds are enclosed within a mature ovary (fruit). They are characterized by double fertilization, where one male gamete fuses with the egg and the other with the secondary nucleus. They exhibit immense diversity in habit, ranging from tiny aquatic Wolffia to massive trees, so not all are trees. Statements 1 and 2 are correct.

Explanation:
Proximal convoluted tubule reabsorbs glucose, amino acids, and most water. Bowman’s capsule surrounds glomerulus; filtrate lacks proteins and cells; collecting duct concentrates urine.

Explanation:
The pineal gland, a small endocrine gland located in the epithalamus of the brain, is often called the 'biological clock' or the 'third eye' in some lower vertebrates. Its primary function in humans is to secrete the hormone melatonin. Melatonin production is regulated by the light-dark cycle (circadian rhythm); it is produced in higher amounts during the night and suppressed by light. Melatonin helps regulate sleep-wake cycles, seasonal reproductive functions, and metabolism.