What is the effect of removing hawks on the number of grasshoppers and rabbits?

Correct Answer: D

Rationale: The correct answer is D because removing hawks would lead to an increase in both grasshoppers and rabbits. Hawks are natural predators of both grasshoppers and rabbits. With fewer hawks preying on them, the populations of grasshoppers and rabbits would increase due to reduced predation pressure. Choice A is incorrect because the removal of hawks would lead to an increase in grasshoppers and rabbits, not no change. Choice B is incorrect because removing hawks would not cause a decrease in grasshoppers but rather an increase. Choice C is incorrect because the removal of hawks would actually result in an increase in the populations of both grasshoppers and rabbits, not no change.

Correct Answer: A

Rationale: The correct answer is A: the distance travelled by light in a vacuum in 1 year. Light-year is a unit of astronomical distance, not time. Light travels at a constant speed in a vacuum, approximately 299,792 kilometers per second. In one year, light can travel about 9.46 trillion kilometers, which is defined as one light-year. Choices B, C, and D are incorrect because they do not accurately define a light-year in terms of distance traveled by light in a vacuum over a specific time period.

Correct Answer: A

Rationale: Correct Answer: A Rationale: 1. Protein kinases add a phosphate group to enzymes through phosphorylation. 2. Phosphorylation alters enzyme activity and can activate or deactivate enzymes. 3. This process regulates enzyme function and signaling pathways. Summary of other choices: B. Incorrect - Protein kinases do not increase enzyme release; they modify enzyme activity. C. Incorrect - Protein kinases do not break down enzymes; they regulate their activity. D. Incorrect - Protein kinases do not increase enzyme secretion; they modify enzyme function through phosphorylation.

Correct Answer: C

Rationale: The correct answer is C because somatostatin acts on nearby cells other than those that secrete it, which is the definition of paracrine signaling. This type of signaling involves the release of signaling molecules that affect neighboring cells within the same tissue or organ. Choices A and B are incorrect because paracrine signaling does not target the cells that secrete the signaling molecule or distant target organs. Choice D is incorrect because the hypothalamus is not typically the target of somatostatin action in the pancreas.

Correct Answer: A

Rationale: The correct answer is A: External laryngeal nerve. This nerve runs along the medial surface of the thyroid gland, providing motor innervation to the cricothyroid muscle. The other choices are incorrect because: B: Hypoglossal nerve innervates the tongue, C: Internal laryngeal nerve supplies sensory innervation to the larynx, and D: Vagus nerve innervates various organs in the thorax and abdomen.