Phycocolloids are found in the cell walls of

Options

A. (a) Diatoms
B. (b) Spirogyra
C. (c) Red and brown algae
D. (d) All algae

Answer

### Step-by-Step Solution:

1. **Understanding Phycocolloids**:
- Phycocolloids are substances that provide protection to marine organisms, particularly from extreme conditions such as freezing and drying.

2. **Identifying the Source of Phycocolloids**:
- These compounds are specifically found in the cell walls of certain types of algae, namely brown and red algae.

3. **Examples of Phycocolloids**:
- In brown algae, the phycocolloid known as algin is present.
- In red algae, two well-known phycocolloids are agar and carrageenan.

4. **Analyzing the Options**:
- Option A (Diatoms): Diatoms are not classified as algae that contain phycocolloids, making this option incorrect.
- Option B (Pyrogyra): Pyrogyra is a type of green algae, which does not contain phycocolloids, so this option is also incorrect.
- Option C (Red and Brown Algae): This option correctly identifies the algae that contain phycocolloids, making it the correct choice.
- Option D (Green Algae): This option includes green algae, which do not contain phycocolloids, thus it is incorrect.

5. **Conclusion**:
- After analyzing all the options, the correct answer is **C: Red and Brown Algae**.