Engleman's experiments with green algae demonstrated that

Options

A. The full spectrum of sunlight is needed for photosynthesis
B. Only red wavelength is effective in causing photosynthesis
C. Only blue wavelength is effective
D. Both blue and red wavelength are effective in causing photosynthesis

Answer

**Step-by-Step Solution:**

1. **Understanding Engleman's Experiment**: Engleman conducted experiments in 1882 using green algae, specifically Spirogyra, to study the effects of different wavelengths of light on photosynthesis.

2. **Objective of the Experiment**: The main goal was to measure how different colors (wavelengths) of light affected the photosynthetic activity of the algae.

3. **Methodology**: Engleman used a prism to split light into its component colors and directed this light onto the algae. He observed the movement of oxygen-producing bacteria towards the algae, indicating where photosynthesis was occurring.

4. **Observations**: Engleman noted that the bacteria congregated more in areas illuminated by blue and red light, suggesting that these wavelengths were more effective for photosynthesis.

5. **Conclusion**: The experiment concluded that both blue and red wavelengths of light are effective in promoting photosynthesis, as indicated by the maximum release of oxygen in these light bands.

6. **Answer Selection**: Based on the findings, the correct answer to the question is that both blue and red wavelengths are effective in causing photosynthesis.

**Final Answer**: Both blue and red wavelengths are effective in causing photosynthesis.

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