The scientist who first observed and described living microorganisms (animalcules) using a single-lens microscope was: MCQ with Answer and Explanation

Explanation:
Veins have thinner walls and larger lumens; arteries are thick and elastic; capillaries are thin for exchange; venules are larger than capillaries. Valves are in veins.

Explanation:
Peristalsis is a wave-like series of muscular contractions and relaxations that propels food through the digestive tract. Segmentation mixes contents in the intestine, emulsification breaks fat globules, mastication is chewing.

Explanation:
Photosynthesis, the process of converting light energy into chemical energy, occurs in the chloroplasts, specifically involving the thylakoid membranes and stroma. Cellular respiration, the process of breaking down glucose to release ATP, occurs primarily in the mitochondria. Transpiration is the loss of water vapor from plants, and while it can occur through lenticels (lenticular transpiration) and the cuticle, the vast majority (about 90%) occurs through the stomata (stomatal transpiration). Thus, statements 1 and 2 are correct.