While the chemical equation for photosynthesis describes the conversion of light into energy, it does not explain the specific molecular triggers that _______ the process within the chloroplasts, a detail that botanists are currently investigating.
Which choice completes the text with the most logical and precise word or phrase?
initiate
obstruct
describe
notice
Correct Answer: A
Choice A is the best answer. The text refers to the "triggers that [blank] the process." Since the process is the result, the triggers are the cause. "Initiate" means to cause (a process or action) to begin.
Choice B is incorrect because "obstruct" means to block. Choice C is incorrect because the triggers cause the process, they don't just "describe" it. Choice D is incorrect because "notice" refers to observation.