I believe the correct answer is Oxygen Gas.
The earth's atmosphere is made up of many different molecules, therefore including the gases. Some common gases are nitrogen, oxygen, and argon, which are only present in traces of percentages. And the gas that occurs as a result of photosynthesis is our answer, oxygen gas.
Hope I could help! :)
Answer:
The yam was the cornerstone of Mongol administration and allowed the Great Khan to run one of the largest empires in history.
Explanation:
I think the answer is A.) fats
This would be the water cycle