Algae which form motile colony are

Options

A. Volvox
B. Nostoc
C. Spirogyra
D. Chlamydomonas

Answer

To solve the question "Algae which form motile colony are," we will analyze the options provided and identify the correct answer step by step.

### Step 1: Understand the Question
The question asks for a type of algae that forms motile colonies. This means we are looking for algae that can move and exist in a colony structure.

**Hint:** Look for characteristics of algae that indicate movement and colony formation.

### Step 2: Identify the Options
The options provided are:
1. Volvox
2. Nostoc
3. Spirogyra
4. Chlamydomonas

**Hint:** Review the characteristics of each type of algae to determine if they form motile colonies.

### Step 3: Analyze Each Option
- **Volvox:** This is a green algae that forms spherical colonies made up of biflagellate cells. These cells are motile due to the presence of flagella, allowing the entire colony to move. Therefore, Volvox forms motile colonies.

- **Nostoc:** This is a filamentous algae that forms colonies in gelatinous sheaths. It does not have flagella and is not motile. Thus, it does not form motile colonies.

- **Spirogyra:** This is also a filamentous green algae that floats on water surfaces. It does not have motile cells and does not form motile colonies.

- **Chlamydomonas:** This is a unicellular green algae that can move due to its flagella, but it does not form colonies that are motile. It forms palmyloid colonies, which are not motile.

**Hint:** Compare the structure and movement capabilities of each algae to determine which one fits the criteria of forming motile colonies.

### Step 4: Conclusion
After analyzing all the options, we conclude that the only algae that forms motile colonies is **Volvox**.

**Final Answer:** The algae which form motile colonies are **Volvox**.