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.
I believe the answer is B. A saturated solution is unable to dissolve any more solvent.
Hope this helps, sorry if I'm wrong.
A, i think, hope this helps:)
Because they create their own food so they capture sunlinght to produce sugars
