Injecting cocaine may cause a hypertensive crisis or stroke, and if the cocaine is inhaled frequently, it may destroy the tissues in the nose. Which of the following best describes how cocaine causes these adverse effects?

Correct Answer: C

Rationale: Cocaine blocks the reuptake of noradrenaline from adrenergic nerves, leading to excessive stimulation of adrenergic receptors. This causes increased blood pressure, which can result in a hypertensive crisis or stroke. Additionally, the vasoconstrictive effects of excess noradrenaline can lead to tissue damage in the nose when cocaine is inhaled frequently. Choices A and B are incorrect because cocaine does not directly block alpha adrenergic or muscarinic receptors. Choice D is incorrect because cocaine does not deplete norepinephrine from adrenergic nerve endings but rather increases its concentration by blocking reuptake.

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: C

Rationale: The correct answer is C: filtrate, evaporation. In process 1, aqueous sodium chloride would form the filtrate after filtration, as the solid residue is left behind. In process 2, evaporation is used to separate the solvent (water) from the dissolved salt, leaving behind the pure salt. Choice A is incorrect because residue is the solid left behind, not the liquid portion (filtrate). Choice B is incorrect as filtration results in the filtrate, not the residue. Choice D is incorrect as the filtrate undergoes evaporation, not filtration.

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.