Which Statement depicts incorrect characteristics of Cyanobacteria ?

Options

A. They have chlorophyll a similar to green plants.
B. They are unicellular, colonial or filamentous from
C. Motile specialized cells " heterocysts" are present which can fix atmosphere nitrogen.
D. They form water bloom in polluted water bodies.

Answer

To determine which statement depicts incorrect characteristics of Cyanobacteria, we will analyze each statement one by one.

### Step 1: Analyze the First Statement
**Statement:** "They have chlorophyll A similar to green plants."
- **Analysis:** Cyanobacteria do indeed contain chlorophyll A, which is similar to that found in green plants. This statement is correct.

### Step 2: Analyze the Second Statement
**Statement:** "Their unicellular colonial filamentous form, motile specialized cell heterocysts are present which can fix atmospheric nitrogen."
- **Analysis:** Cyanobacteria can exist in unicellular, colonial, or filamentous forms. They also have specialized cells known as heterocysts that can fix atmospheric nitrogen. However, the statement incorrectly describes heterocysts as "motile specialized cells." Heterocysts are not motile; they are specialized for nitrogen fixation. Therefore, this statement is partially incorrect.

### Step 3: Analyze the Third Statement
**Statement:** "Motile specialized cell heterocysts are present which can fix atmospheric nitrogen."
- **Analysis:** This statement is incorrect because heterocysts are not motile. They are specialized cells that fix nitrogen but do not have the ability to move. This is the incorrect characteristic of Cyanobacteria.

### Step 4: Analyze the Fourth Statement
**Statement:** "They form water bloom in polluted water bodies."
- **Analysis:** Cyanobacteria can indeed form water blooms in polluted water bodies, especially when there is an excess of nutrients. This statement is correct.

### Conclusion
The statement that depicts incorrect characteristics of Cyanobacteria is the third statement: "Motile specialized cell heterocysts are present which can fix atmospheric nitrogen." Heterocysts are not motile.