Products of light reaction are

Options

A. `O_2` and `CO_2`
B. `CO_2` and `H_2O`
C. ATP and NADPH
D. ATP and `CO_2`

Answer

To answer the question about the products of the light reaction in photosynthesis, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Light Reactions**: Light reactions occur in the thylakoid membranes of chloroplasts during the daytime when sunlight is available. They convert light energy into chemical energy.

2. **Identifying Key Products**: The primary products of the light reactions are:
- **ATP (Adenosine Triphosphate)**: This molecule serves as an energy currency for the cell.
- **NADPH (Nicotinamide Adenine Dinucleotide Phosphate)**: This molecule acts as a reducing agent, providing the necessary electrons for the synthesis of glucose in the dark reactions.

3. **Oxygen Production**: During the light reactions, water (H2O) is split (a process known as photolysis), releasing oxygen (O2) as a byproduct. However, O2 is not considered a product that is utilized in the subsequent dark reactions.

4. **Distinguishing Between Light and Dark Reactions**: It's important to note that while ATP and NADPH are produced in the light reactions, glucose is produced in the dark reactions (Calvin cycle) using the ATP and NADPH generated.

5. **Eliminating Incorrect Options**:
- CO2 is not a product of the light reaction; it is utilized in the dark reactions.
- H2O is consumed in the light reaction but is not a product.
- Any combination of ATP with CO2 is incorrect since CO2 is not produced in the light reaction.

6. **Conclusion**: The correct answer to the question about the products of the light reaction is that they are ATP and NADPH.

### Final Answer:
The products of the light reaction are **ATP and NADPH**.

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