Fresh water photosynthetic protists of stagnant water shows dual behaviour in :

Options

A. nutrition and reproduction
B. respiration and spore formation
C. nutrition and movement
D. locomotion and respiration

Answer

**Step-by-Step Solution:**

1. **Identify the Organism**: The question refers to freshwater photosynthetic protists found in stagnant water, specifically euglenoids.

2. **Characteristics of Euglenoids**:
- Euglenoids are unicellular eukaryotes.
- They lack a cell wall; instead, they have a flexible protein-rich layer called a pellicle.
- They are biflagellate, meaning they possess two flagella of unequal lengths.

3. **Reproduction**:
- Euglenoids primarily reproduce asexually through binary fission, specifically longitudinal binary fission.
- Sexual reproduction is generally absent in euglenoids.

4. **Nutrition**:
- Euglenoids exhibit mixotrophic nutrition, which means they can obtain energy through different methods depending on environmental conditions.
- When sunlight is available, they perform photosynthesis (photoautotrophic mode).
- In the absence of sunlight, they can switch to a heterotrophic mode, consuming organic matter or performing phagocytosis.

5. **Conclusion**:
- The dual behavior of euglenoids is primarily observed in their mode of nutrition (mixotrophic) and their movement (due to the presence of flagella).
- Therefore, the correct answer to the question is that freshwater photosynthetic protists (euglenoids) show dual behavior in nutrition and movement.

**Final Answer**: Freshwater photosynthetic protists of stagnant water show dual behavior in nutrition and movement.

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