Correct Answer: D

Rationale: A common finding in a whiplash injury is a traumatic injury to ligaments. Whiplash occurs due to sudden hyperextension and hyperflexion of the neck, leading to strain or tearing of ligaments in the neck. This can manifest as neck pain, stiffness, and limited range of motion. While other complications like cardiopulmonary problems, side-to-side spinal curvature, or eventual herniation of discs are not typically associated with whiplash injuries.

Correct Answer: D

Rationale: The mitral valve, also known as the bicuspid valve, separates the left atrium and the left ventricle of the heart. Its primary function is to prevent the backflow of blood from the left ventricle to the left atrium during the heart's contraction. Therefore, option D, 'Left atrium and left ventricle,' is the correct answer. Choices A, B, and C are incorrect because they do not represent the parts separated by the mitral valve.

Correct Answer: B

Rationale: The correct answer is B: Quadriceps femoris. The quadriceps femoris is an anterior muscle located on the front of the thigh. It is composed of four muscles: rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. These muscles play a crucial role in extending the knee and are essential for activities like walking, running, and jumping. Choices A, C, and D are incorrect because they are not anterior muscles of the thigh. Gluteus maximus is a muscle located in the buttocks, biceps femoris is a muscle of the posterior thigh, and adductor magnus is a muscle of the medial thigh.

Correct Answer: C

Rationale: Muscle contractions that move food along the human digestive system are known as peristalsis. Peristalsis consists of a series of coordinated muscular contractions and relaxations that help propel food through the esophagus, stomach, and intestines, facilitating efficient digestion and nutrient absorption. Defecation refers to expelling waste from the body, osmosis is the movement of water across a membrane, and circulation relates to the movement of blood in the body's circulatory system, not directly involved in food transportation along the digestive tract.

Correct Answer: D

Rationale: The correct answer is D. Parathyroid hormone plays a crucial role in activating vitamin D. This activation occurs in the kidneys, where parathyroid hormone stimulates the conversion of inactive vitamin D to its active form. Active vitamin D is essential for maintaining proper levels of calcium and phosphorus in the body, which are important for bone health and other physiological functions. Choices A, B, and C are incorrect because parathyroid hormone is not involved in increasing energy levels, stimulating cell reproduction, or speeding up metabolism. Its primary function is related to calcium and phosphorus homeostasis through the activation of vitamin D.