Which of the following substances are inputs (reactants) in the process of photosynthesis?

• A. Oxygen (\(\mathrm{O_2}\)) and carbon dioxide (\(\mathrm{CO_2}\))
• B. Carbon dioxide (\(\mathrm{CO_2}\)) and water (\(\mathrm{H_2O}\))
• C. Oxygen (\(\mathrm{O_2}\)) and glucose (\(\mathrm{C_6H_{12}O_6}\))
• D. Glucose (\(\mathrm{C_6H_{12}O_6}\)) and water (\(\mathrm{H_2O}\))

Answer: (B)

Verified step by step guidance

1. Step 1: Begin by recalling the overall chemical equation for photosynthesis. Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy stored in glucose. The general equation is: \$6\mathrm{CO_2} + 6\mathrm{H_2O} + \text{light energy} \rightarrow \mathrm{C_6H_{12}O_6} + 6\mathrm{O_2}$.
2. Step 2: Identify the reactants (inputs) in the equation. Reactants are the substances that are consumed during the reaction. In the photosynthesis equation, the reactants are carbon dioxide (\(\mathrm{CO_2}\)) and water (\(\mathrm{H_2O}\)).
3. Step 3: Understand the role of each reactant. Carbon dioxide (\(\mathrm{CO_2}\)) is absorbed from the atmosphere through the stomata of plant leaves, and water (\(\mathrm{H_2O}\)) is absorbed from the soil through the roots. These reactants are used in the light-independent reactions (Calvin cycle) and light-dependent reactions, respectively.
4. Step 4: Eliminate incorrect options based on the chemical equation. Oxygen (\(\mathrm{O_2}\)) and glucose (\(\mathrm{C_6H_{12}O_6}\)) are products of photosynthesis, not reactants. Similarly, glucose (\(\mathrm{C_6H_{12}O_6}\)) and water (\(\mathrm{H_2O}\)) cannot both be reactants because glucose is synthesized during the process.
5. Step 5: Conclude that the correct answer is carbon dioxide (\(\mathrm{CO_2}\)) and water (\(\mathrm{H_2O}\)), as these are the substances consumed during photosynthesis to produce glucose and oxygen.