Chlorophyll containing euglenoid species are

Options

A. Facultative autotrophs
B. Obligate autotrophs
C. Obligate heterotrophs
D. Facultative heterotrophs.

Answer

To solve the question regarding chlorophyll-containing euglenoid species, we will analyze the nutritional modes of Euglena, a well-known euglenoid.

### Step-by-Step Solution:

1. **Identify the Organism**: The question refers to chlorophyll-containing euglenoid species, specifically Euglena, which belongs to the kingdom Protista and is a unicellular eukaryote.

2. **Understand the Nutritional Modes**: Euglena can perform photosynthesis due to the presence of chlorophyll. This means it can produce its own food when light is available, which categorizes it as an autotroph.

3. **Autotrophic Mode**: In the presence of light, Euglena primarily utilizes the autotrophic mode of nutrition, where it synthesizes its own food through photosynthesis.

4. **Heterotrophic Mode**: In the absence of light, Euglena can switch to a heterotrophic mode of nutrition, where it consumes organic matter or small organisms like plankton for sustenance.

5. **Define Facultative and Obligate**:
- **Facultative** means the organism can switch between different modes of nutrition depending on environmental conditions.
- **Obligate** means the organism has only one fixed mode of nutrition and cannot switch.

6. **Analyze the Options**:
- **Facultative Autotrophs**: This would imply that Euglena's main mode is heterotrophic, which is incorrect.
- **Obligate Autotrophs**: This would mean Euglena can only perform photosynthesis, which is also incorrect as it can switch to heterotrophy.
- **Obligate Heterotrophs**: This would imply Euglena can only feed on organic matter, which is incorrect.
- **Facultative Heterotrophs**: This is correct because Euglena primarily performs photosynthesis (autotrophic) but can switch to heterotrophy when light is absent.

7. **Conclusion**: Therefore, the correct answer is that chlorophyll-containing euglenoid species are **facultative heterotrophs**.

### Final Answer:
Chlorophyll containing euglenoid species are **facultative heterotrophs**.