1. Which hormone is primarily responsible for the regulation of plasma glucose levels? A. Insulin B. Glucagon C. Cortisol D. Epinephrine Answer: A. Insulin Rationale: Insulin, produced by the pancreas, is the hormone that lowers blood glucose levels by facilitating the uptake of glucose into tissues. 2. During inhalation, which of the following muscles contract to increase thoracic cavity volume? A. External intercostals and diaphragm B. Internal intercostals and diaphragm C. Abdominal muscles and diaphragm D. Pectoralis minor and diaphragm Answer: A. External intercostals and diaphragm Rationale: Inhalation is facilitated by the contraction of the external intercostal muscles and the diaphragm, which increase the volume of the thoracic cavity and decrease the pressure inside, allowing air to flow into the lungs. 3. What is the primary function of the lymphatic system? A. Transporting nutrients to the bloodstream B. Regulating body temperature C. Maintaining fluid balance and protecting against infection D. Producing hormones for digestion Answer: C. Maintaining fluid balance and protecting against infection Rationale: The lymphatic system helps maintain fluid balance by returning excess tissue fluid to the bloodstream and plays a key role in the body's immune defense mechanisms. 4. Which type of joint allows for the widest range of motion? A. Hinge joint B. Pivot joint C. Ball-and-socket joint D. Saddle joint Answer: C. Ball-and-socket joint