3. Explain the role of organisms in the carbon
cycle and oxygen cycle ​

What organism? If its plants, they give oxygen during the day and carbon dioxide in the night. While animals give carbon dioxide but take oxygen from the air. These carbon dioxide gas and oxygen gas go to the atmosphere and affect the carbon cycle and oxygen cycle.

Here is the cycle if you want to know more

Plants (give out oxygen) -> Animals (Use oxygen) + (given our carbon dioxide) -> plants (take oxygen)

and so on

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.