The hormone responsible for the male secondary sexual characteristics is: MCQ with Answer and Explanation

Explanation:
Thyroxine (T4) and Triiodothyronine (T3) are the main hormones secreted by the thyroid gland. They play a crucial role in regulating the basal metabolic rate (BMR), which is the rate at which the body uses energy at rest. They also influence growth, development, and body temperature. Calcitonin, also from the thyroid, regulates blood calcium.

Explanation:
Gastrin is a hormone secreted by G cells in the stomach antrum, stimulating parietal cells to secrete HCl and promoting gastric motility. It is released in response to food in the stomach.

Explanation:
Crassulacean Acid Metabolism (CAM) plants, such as cacti and succulents, adapt to arid environments by opening their stomata at night to fix CO2 into organic acids (like malic acid) and storing them in vacuoles. During the day, the stomata close to prevent water loss, and the stored CO2 is released for the Calvin cycle.