Assertion (A): The cell wall of fungi is made of cellulose. Reason (R): Chitin is a characteristic component of fungal cell walls. MCQ with Answer and Explanation

Explanation:
Amphioxus (Branchiostoma) is a primitive chordate possessing a notochord, dorsal nerve cord, and pharyngeal slits throughout life, but lacking a vertebral column; hence it is an invertebrate chordate. Earthworm is an annelid, cockroach an arthropod, starfish an echinoderm—all non-chordates. Vertebrate chordates include fishes, amphibians, reptiles, birds, and mammals. Amphioxus is studied for evolutionary insights into vertebrate origins.

Explanation:
Andreas Schimper first described chloroplasts and coined the term in 1883. Hooke discovered cells, Leeuwenhoek observed live cells, Sachs showed starch is produced by photosynthesis.

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.