In which phase of mitosis do chromosomes align at the equatorial plate? MCQ with Answer and Explanation

Explanation:
Aldosterone is a mineralocorticoid hormone secreted by the zona glomerulosa, the outermost layer of the adrenal cortex. Its primary function is to regulate electrolyte balance by promoting the active reabsorption of sodium (Na+) and the excretion of potassium (K+) and hydrogen ions (H+) in the distal tubules and collecting ducts of the kidneys. The zona fasciculata secretes glucocorticoids (cortisol).

Explanation:
Calcitonin, produced by parafollicular (C) cells of the thyroid gland, lowers blood calcium by inhibiting osteoclast activity and promoting calcium deposition in bones. Parathyroid hormone (PTH) raises calcium. Adrenal cortex secretes corticosteroids, pancreas secretes insulin/glucagon. Calcitonin opposes PTH.

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.