Correct Answer: B

Rationale: Adrenaline, also known as epinephrine, is the correct hormone produced by the adrenal medulla. It plays a crucial role in the body's fight-or-flight response, increasing heart rate, dilating airways, and mobilizing energy stores to prepare the body for perceived threats. Insulin (Choice A) is produced by the pancreas and regulates blood sugar levels, not by the adrenal medulla. Cortisol (Choice C) is produced by the adrenal cortex and is involved in regulating metabolism, immune response, and stress. Melatonin (Choice D) is produced by the pineal gland and regulates the sleep-wake cycle.

Correct Answer: B

Rationale: The correct answer is B: Ball and socket joint. The hip joint is classified as a ball and socket joint, allowing for a wide range of movement in multiple directions, including rotation. This joint structure provides stability and mobility, making it ideal for the hip's functions in bearing weight and facilitating various movements. Choice A, Hinge joint, is incorrect as hinge joints allow movement in only one plane, like the elbow or knee. Choice C, Pivot joint, is incorrect as pivot joints allow rotation around a single axis, like the joint between the first and second vertebrae. Choice D, Saddle joint, is incorrect as saddle joints are found in the thumb and allow movement in two planes, but they do not describe the hip joint.

Correct Answer: A

Rationale: The parathyroid gland is not involved in the release of hormones during stress. It is responsible for regulating calcium levels in the blood by secreting parathyroid hormone. During stress, the adrenal cortex, posterior pituitary, and hypothalamus play crucial roles in releasing stress hormones like cortisol, adrenaline, and oxytocin. Therefore, the correct answer is the parathyroid gland, as it is not directly associated with the release of stress-related hormones.

Correct Answer: A

Rationale: The main function of the circulatory system is to transport oxygen and nutrients to the body's cells while removing waste products. Oxygen and nutrients are carried by the blood to various tissues and organs, ensuring they receive essential elements for their proper function. Waste products are then removed from the cells and transported to the appropriate organs for elimination. This process ensures the overall well-being and functionality of the body. Choice B, removing waste products, is partially correct as one of the functions of the circulatory system is indeed to eliminate waste from the body. However, the primary function is to transport oxygen and nutrients. Choice C, regulating body temperature, is incorrect as temperature regulation is mainly controlled by the body's respiratory and integumentary systems. Choice D, protecting organs, is not a primary function of the circulatory system; protection is more closely associated with the immune system and the skeletal system.

Correct Answer: A

Rationale: Insulin is the correct answer. Insulin is produced by the pancreas and plays a crucial role in regulating blood glucose levels. It facilitates the uptake of glucose into cells, helping to lower blood sugar levels. Glucagon, on the other hand, is also produced by the pancreas but functions to raise blood glucose levels by stimulating the release of glucose from the liver. Somatostatin is another hormone produced by the pancreas that helps regulate the endocrine system. Cortisol, produced by the adrenal glands, plays a role in stress response and metabolism, not by the pancreas.