Phototaxis is shown by

Options

A. Zoospores of Ulothrix
B. Chlamydomonas
C. Volvox
D. All of above.

Answer

**Step-by-Step Solution:**

1. **Understanding Phototaxis**: Phototaxis refers to the movement of an organism or a part of an organism in response to light. It can be positive (movement towards light) or negative (movement away from light).

2. **Identifying Organisms**: The question lists several options: zoospores of Elothrix, Chlamydomonas, and Volvox. We need to determine if these organisms exhibit phototaxis.

3. **Examining Elothrix**: Elothrix is a type of green algae. It is known to exhibit positive phototaxis, meaning its zoospores move towards light.

4. **Examining Chlamydomonas**: Chlamydomonas is another type of green algae that also shows positive phototaxis. Its cells can swim towards light sources.

5. **Examining Volvox**: Volvox is a colonial green algae that also exhibits phototaxis. The individual cells within the colony can move towards light.

6. **Conclusion**: Since all three organisms (zoospores of Elothrix, Chlamydomonas, and Volvox) exhibit phototaxis, the correct answer to the question is "all of the above."

**Final Answer**: Phototaxis is shown by all of the above: zoospores of Elothrix, Chlamydomonas, and Volvox.

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