Correct Answer: B

Rationale: Cartilage is the correct answer as it is the substance that makes up the pads between the vertebrae. Cartilage provides cushioning and support between the bones of the spine, allowing for flexibility and preventing friction between the vertebrae. Bone (choice A) is incorrect as it forms the structure of the vertebrae, not the intervertebral discs. Tendon (choice C) is incorrect as it connects muscle to bone and is not found between the vertebrae. Fat (choice D) is incorrect as it is not the substance that makes up the pads between the vertebrae.

Correct Answer: C

Rationale: The pituitary gland, often referred to as the 'master gland,' controls the release of hormones from other endocrine glands in the body. It secretes various hormones that regulate many bodily functions, making it a central and vital component of the endocrine system. The thyroid gland (Choice A) regulates metabolism, the adrenal gland (Choice B) produces hormones like adrenaline, and the pineal gland (Choice D) secretes melatonin, but none of these glands are considered the 'master gland' that controls the functions of other endocrine glands.

Correct Answer: A

Rationale: The correct answer is the pancreas. The pancreas is responsible for producing insulin, a hormone crucial for regulating blood glucose levels. Insulin plays a key role in allowing cells to take in glucose, thereby helping to keep blood sugar levels in check. The liver (choice B), gallbladder (choice C), and kidneys (choice D) do not produce insulin. The liver is involved in glycogen storage and glucose regulation, the gallbladder stores bile, and the kidneys filter blood and regulate fluid balance.

Correct Answer: A

Rationale: The cochlea, situated in the inner ear, is responsible for detecting sound waves and converting them into neural signals that are transmitted to the brain for processing. The cochlea contains specialized sensory cells that respond to different frequencies of sound, allowing us to hear a wide range of sounds. The other structures listed, such as the eustachian tube, ossicles, and semicircular canals, play roles in functions like equalizing pressure, transmitting vibrations, and maintaining balance, respectively, but they are not directly involved in the detection of sound.

Correct Answer: C

Rationale: The correct answer is C: Medulla oblongata. The medulla oblongata, situated in the brainstem, plays a crucial role in regulating vital functions such as heart rate, breathing, and blood pressure. It serves as the control center for involuntary actions, ensuring the body's automatic functions work properly. Choices A, B, and D are incorrect because the cerebrum is primarily responsible for functions such as thinking, voluntary movements, and sensory processing; the cerebellum is involved in coordination, balance, and muscle control; and the hypothalamus regulates body temperature, thirst, hunger, and some aspects of the autonomic nervous system but not specifically heart rate and breathing.