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**:
- Euglena is a single-celled organism that exhibits characteristics of both plants and animals. It has chloroplasts which allow it to perform photosynthesis in the presence of light.

2. **Analyzing the Options**:
- The question presents four options regarding the predatory nature of Euglena.

3. **Option 1**:
- **Statement**: "In the presence of light, Euglena is a predator of small organisms."
- **Analysis**: This statement is incorrect because, in the presence of light, Euglena primarily performs photosynthesis due to its chloroplasts, thus making it autotrophic rather than predatory.

4. **Option 2**:
- **Statement**: "Due to holophytic nutrition, Euglena is a predator of small organisms."
- **Analysis**: This statement is also incorrect. Holophytic nutrition refers to the ability to produce food through photosynthesis. Since Euglena can make its own food in the presence of light, it cannot be classified as a predator under these conditions.

5. **Option 3**:
- **Statement**: "Due to mixotropic nutrition, Euglena is a predator of small organisms."
- **Analysis**: Mixotropic nutrition means the organism can utilize both autotrophic and heterotrophic modes of nutrition. While Euglena can be heterotrophic in the absence of light, this option does not directly state the conditions under which it becomes predatory.

6. **Option 4**:
- **Statement**: "In the absence of light, Euglena is a predator of small organisms."
- **Analysis**: This statement is correct. In the absence of light, Euglena cannot perform photosynthesis and must rely on heterotrophic nutrition, thus becoming a predator of small organisms.

7. **Conclusion**:
- The correct answer is **Option 4**: "In the absence of light, Euglena is a predator of small organisms."