C because oxygen was a byproduct of photosynthesis and proved to be EXTREMELY important in the atmosphere.
Answer: Option D
Explanation:
The practice which has been prevailing from a long time is considered as culture.Farming is also a type of culture which is being practiced from a longer period of time in the society.
The farming is also a type of culture which was invented somewhere and started spreading from there to other places.
This practice helped mankind in providing food and resources to the people of nation.
In an experiment the HYPOTHESIS is tested. The hypothesis is the assumption, that you make about something. Example would be, you believe (hypothesize) that the baking soda will react faster in vinegar than in water. You then test it out (or preform and experiment) to see if your hypothesis is correct or wrong.
Choice answer D because it is fully correct
