Consider statements about scientists: 1. Carolus Linnaeus developed binomial nomenclature. 2. Louis Pasteur developed the rabies vaccine. 3. Gregor Mendel discovered the structure of DNA. Which are correct? MCQ with Answer and Explanation

Explanation:
The pituitary gland is termed the master gland because it secretes hormones that regulate other endocrine glands. The thyroid gland secretes thyroxine, triiodothyronine, and calcitonin, which regulates blood calcium. The adrenal cortex secretes cortisol (a glucocorticoid), while the adrenal medulla secretes adrenaline and noradrenaline. Thus, statements 1 and 2 are correct.

Explanation:
The joints between skull bones are immovable fibrous joints called sutures, where bones are tightly connected by dense connective tissue. Hinge joint (elbow, knee) allows movement in one plane. Ball and socket (shoulder, hip) allows multi-directional movement. Pivot joint (atlas-axis) allows rotational movement. Sutures fuse completely in old age.

Explanation:
Amphibia (e.g., frogs, toads, salamanders) are characterized by their dual habitat (amphi = both, bios = life). They can live in water and on land. They have moist, glandular skin without scales, which aids in respiration. They typically have a larval stage (tadpole) that undergoes metamorphosis to become an adult.