Because, it is the process by which they make or produce their food with the help of sunlight, water and carbon dioxide.
If photsynthesis is not there then there would be no production of food and ultimatley plants will die.
Another name for unicellular organisms that dominated Earth up to the Precambrian time is prokaryotes. The correct answer is D.
We would call this scientific research
ans is D. Most items are features in the spinal cord, but the hippocampus is in the brain.
