I. Green algae occur in fresh water, brackish water salt water.
II. Habitat of Brown algae-fresh water (rare), brackish water, salt water
IIl. Some red algae are found in fresh water, mostly occur in salt water, some are in brackish water
IV. Most of the red algae are multicellular.
V. Red algae may occur in both well lighted regions close to water-surface and also at great depths in oceans where light penetration is little.
VI. Cell wall of red algae consists of cellulose + polysulphate easters.
VII. 2-8, equal and apical flagella in green algae

Options

A. All are correct
B. All are false
C. l and VI are correct
D. II, III and V are correct

Answer

### Step-by-Step Solution:

1. **Understanding the Types of Algae**:
- Algae are classified into three main groups: green algae, brown algae, and red algae. Each type has distinct characteristics and habitats.

2. **Analyzing the Statements**:
- **Statement I**: Green algae can be found in fresh water, brackish water, and salt water. This is correct as green algae are versatile and adapt to various aquatic environments.
- **Statement II**: Brown algae are rarely found in fresh water, primarily inhabiting brackish and salt water. This is also accurate, as brown algae predominantly thrive in marine environments.
- **Statement III**: Some red algae are found in fresh water, but they mostly occur in salt water, with some in brackish water. This statement is true, as red algae are primarily marine organisms.
- **Statement IV**: Most red algae are multicellular. This is correct; red algae typically exhibit multicellularity.
- **Statement V**: Red algae can be found in well-lighted regions close to the water surface and at great depths where light penetration is minimal. This is true, as red algae can adapt to varying light conditions.
- **Statement VI**: The cell wall of red algae consists of cellulose and polysulphate esters. This is accurate; red algae have a unique cell wall composition.
- **Statement VII**: Green algae have 2-8 equal and apical flagella. This is correct, as green algae are characterized by this flagellar arrangement.

3. **Conclusion**:
- Since all the statements provided are correct, the answer is that all statements regarding algae are true.

### Final Answer:
All statements are correct.

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