Stratovolcanoes seems to fit, but I do not know what the list of answer choices is. Hope this if helpful :)
Answer:
On a simplified level, photosynthesis and cellular respiration are opposite reactions of each other. In photosynthesis, solar energy is harvested as chemical energy in a process that converts water and carbon dioxide to glucose. Oxygen is released as a byproduct.
The generally widely accepted first step of the scientific method is to ask a question.
This is where you think of a question which you want to do an experiment on, and then later on conduct an experiment to answer that question.