Correct Answer: B

Rationale: Adrenaline, also known as epinephrine, is released by the adrenal glands during stress to prepare the body for rapid action. It helps in triggering the body's fight-or-flight response, increasing heart rate, and providing a burst of energy when faced with stressful situations. Insulin (Choice A) is produced by the pancreas to regulate blood sugar levels, not by the adrenal glands. Melatonin (Choice C) is a hormone that regulates sleep-wake cycles and is produced by the pineal gland, not the adrenal glands. Cortisol (Choice D) is another hormone produced by the adrenal glands, but it is not the primary hormone released during immediate stress responses; it is more involved in long-term stress regulation.

Correct Answer: B

Rationale: The epidermis is the correct answer as it is the outermost layer of the skin. It acts as a protective barrier against environmental factors and helps in regulating moisture balance. The epidermis is also where new skin cells are continuously formed and contains melanocytes responsible for skin pigmentation. Choices A, C, and D are incorrect. The dermis is the layer beneath the epidermis, the subcutaneous tissue is the deepest layer of the skin, and the hypodermis lies below the dermis.

Correct Answer: A

Rationale: Corrected Rationale: Damage to the ulnar nerve typically results in decreased sensation in the hand, particularly affecting the little finger and half of the ring finger. The ulnar nerve innervates the hand and is responsible for providing sensation to these areas. This nerve does not extend to the leg or foot, so choices C and D are incorrect. While the ulnar nerve travels through the arm, its primary sensory impact is felt in the hand, making choice B less specific and therefore not the best answer.

Correct Answer: B

Rationale: The primary function of platelets, or thrombocytes, is to clot blood. Platelets play a crucial role in hemostasis by forming clots to prevent excessive bleeding when injuries occur. They are not directly involved in fighting infections, carrying oxygen, or transporting nutrients. Therefore, the correct answer is B.

Correct Answer: A

Rationale: The correct answer is 'Larynx.' The larynx is indeed located in the upper respiratory system alongside the pharynx. Positioned below the pharynx and above the trachea, the larynx is crucial for breathing and sound production. The trachea and bronchi are part of the lower respiratory system and are situated below the larynx, making them incorrect choices in this context.