Of the following group which secrete and deposit calcium carbonate and appear like corals.

Options

A. Red algae
B. Brown algae
C. Blue-green algae
D. All the above.

Answer

To solve the question "Of the following group which secrete and deposit calcium carbonate and appear like corals?" we will analyze the options provided:

1. **Identify the Groups**: The options given are:
- A. Red Algae
- B. Brown Algae
- C. Blue Green Algae
- D. All of the above

2. **Understand the Characteristics**:
- **Red Algae**: These algae belong to the group known as Rhodophyta. They are known for their ability to secrete and deposit calcium carbonate, which contributes to the formation of hard structures that resemble corals. The presence of calcium carbonate in their cell walls gives them a hard thallus.
- **Brown Algae**: This group, known as Phaeophyta, does not secrete calcium carbonate. They are typically larger and include species like kelp, but they do not have the same hard structure as corals.
- **Blue Green Algae**: Also known as Cyanobacteria, these are not true algae and do not secrete calcium carbonate. They are more primitive and do not form hard structures like corals.
- **All of the Above**: This option suggests that all the groups mentioned secrete calcium carbonate, which is incorrect based on the characteristics of brown and blue-green algae.

3. **Conclusion**: Based on the analysis, the only group that secretes and deposits calcium carbonate and appears like corals is **Red Algae**.

Thus, the answer to the question is **Option A: Red Algae**.