Plants manufacture their food with the help of —

Concept: Photosynthesis is the process by which green plants prepare their own food (glucose) using carbon dioxide and water in the presence of sunlight, with the pigment chlorophyll capturing the light energy; oxygen is released as a byproduct. This is summed up by the reaction 6CO2 + 6H2O + light energy → C6H12O6 + 6O2.

Application: To carry out this reaction, a plant needs three inputs: water absorbed through the roots, sunlight as the energy source captured by chlorophyll, and carbon dioxide absorbed from the air through the stomata. These three combine inside the chloroplast to build glucose; oxygen is what comes out of the process, not what goes into it.

Cross-check / contrast with the other option-sets:

• Oxygen, Sunlight, Water: swaps in oxygen, the released byproduct, in place of carbon dioxide, the gas the plant actually draws in from the air as a reactant.

• Carbon dioxide, Oxygen, Sunlight: again treats the released byproduct oxygen as an input, and drops water, the liquid reactant absorbed by the roots.

• Oxygen, Sunlight: repeats the same oxygen-for-input mix-up, and lists only two items where three (water, sunlight, carbon dioxide) are needed.

Result: Water, sunlight, and carbon dioxide are therefore the three raw materials/conditions a plant uses to manufacture its food.