Question

for what purpose is sunlight used in the process of photosynthesis?
a photolysis of water
b as a direct source of electrons
c for fixing carbon dioxide
d none of the above

Explanation:

• In photosynthesis, sunlight is used for photolysis of water. Sunlight provides the energy to split water molecules ($\ce{H2O}$) into oxygen ($\ce{O2}$), protons ($\ce{H+}$), and electrons.
• Option b: Sunlight is not a direct source of electrons. Electrons come from water during photolysis.
• Option c: Carbon dioxide fixation (Calvin cycle) does not directly use sunlight. It uses ATP and NADPH produced in the light - dependent reactions (which use sunlight).

Answer:

A. Photolysis of water