Euglena is a predator of small organisms :

Options

A. in presence of light
B. due to holophytic nutrition
C. due to mixotrophic nutrition
D. in absence of light

Answer

**Step-by-Step Solution:**

1. **Understanding Euglena**: Begin by recognizing that Euglena is a genus of single-celled organisms that belong to the group known as euglenoids, which are classified under the kingdom Protista.

2. **Nutritional Modes**: Euglena exhibits a unique nutritional behavior known as mixotrophy, which means it can obtain nutrients in multiple ways. It can perform photosynthesis when light is available and can also consume small organisms when light is absent.

3. **Photosynthesis in Light**: In the presence of light, Euglena utilizes its chlorophyll A and B pigments to carry out photosynthesis. This process allows it to produce its own food, similar to plants.

4. **Heterotrophy in Darkness**: When light is not available, Euglena switches to a heterotrophic mode of nutrition. In this mode, it can engulf and digest small organisms through a process called phagocytosis.

5. **Analyzing the Options**: The question presents options regarding when Euglena acts as a predator:
- In the presence of light (incorrect, as it performs photosynthesis).
- Due to holophytic nutrition (incorrect, as this refers to photosynthesis).
- Due to myxotrophic nutrition (partially correct, but needs context).
- In the absence of light (correct, as it switches to heterotrophic nutrition).

6. **Conclusion**: The correct answer is that Euglena acts as a predator of small organisms in the absence of light, as it relies on heterotrophic nutrition during that time.

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