Correct Answer: B

Rationale: The correct answer is B, Hip. The hip joint is a ball-and-socket joint, characterized by the spherical head of one bone (femur) fitting into the cup-like socket of another bone (pelvis). This structure allows for a wide range of motion in multiple directions, such as flexion, extension, abduction, adduction, and rotation. Choices A, C, and D are incorrect as the knee, elbow, and wrist joints are not ball-and-socket joints. The knee is a hinge joint, allowing flexion and extension movements. The elbow is a hinge joint that allows flexion and extension, while the wrist is a condyloid joint permitting flexion, extension, abduction, adduction, and circumduction movements.

Correct Answer: B

Rationale: The correct answer is B, 'Larynx.' The larynx is commonly referred to as the voice box because it plays a crucial role in sound production. It contains vocal cords and functions in speech and singing. Choice A, 'Alveoli,' are small air sacs in the lungs involved in gas exchange. Choice C, 'Trachea,' is the windpipe that connects the larynx to the bronchi. Choice D, 'Pharynx,' is the throat area located behind the mouth and nasal cavity, responsible for the passage of food and air.

Correct Answer: D

Rationale: The correct answer is the sympathetic nervous system. It controls the 'fight or flight' response by preparing the body for stressful situations. The central nervous system (Choice A) consists of the brain and spinal cord but does not directly control the 'fight or flight' response. The peripheral nervous system (Choice B) includes nerves outside the brain and spinal cord, while the autonomic nervous system (Choice C) regulates involuntary bodily functions but is not specific to the 'fight or flight' response.

Correct Answer: B

Rationale: The P-wave in an ECG represents the depolarization of the SA node and the atria, not atrial repolarization. Choice C, ventricular depolarization, is incorrect because the P-wave does not correspond to ventricular activity. Choice D, ventricular repolarization, is also incorrect as the P-wave does not depict ventricular repolarization. The correct interpretation is that the P-wave signifies the initiation of the electrical impulse at the SA node and subsequent atrial depolarization, making option B the correct answer.

Correct Answer: D

Rationale: The correct answer is the cardiovascular system (Option D). The cardiovascular system is responsible for transporting oxygenated blood from the lungs, where oxygen is absorbed, to various tissues and organs in the body, including the spleen. The immune system (Option A) is responsible for defending the body against infections and diseases. The endocrine system (Option B) regulates hormones and their effects on the body. The respiratory system (Option C) is responsible for the exchange of gases, such as oxygen and carbon dioxide, in the lungs.