I believe the correct answer from the choices listed above is the third option. It is oxygen that is a necessary reactant for cellular respiration to occur. Cellular respiration, in a sense, is breaking down sugar in the presence of oxygen. Hope this answers the question.
Answer:
Homeostasis
Explanation:
It is what makes to where you are a warm enough temperature that's not to hot and not to cold. It tells all the cells in that one part of your body what to do keep it balanced. If you don't understand this just comment on my answer and say what you need to tell me so I know what to adjust so you can understand it.
The water cycle is the correct answer, the water evaporates, then condenses into clouds, and turns into rain and precipitation occurs.
Answer:
An infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a host.
