All of the following statements are correct for blue green algae, except

Options

A. they have chlorophyll- a, which is also found in higher plants.
B. they may be filamentous, colonial , or unicellular.
C. they have heterocysts which are clear cells without chlorophyll.
D. they are connecting link between plants and animals.

Answer

To solve the question regarding blue-green algae (cyanobacteria) and identify the incorrect statement, we will analyze each of the provided statements step by step.

### Step 1: Analyze the first statement
**Statement:** Blue-green algae have chlorophyll A, which is also found in higher plants.

**Analysis:** This statement is correct. Blue-green algae contain chlorophyll A, which is essential for photosynthesis and is also found in higher plants.

### Step 2: Analyze the second statement
**Statement:** Blue-green algae may be filamentous, colonial, or unicellular.

**Analysis:** This statement is also correct. Blue-green algae can exist in various forms, including filamentous (long chains of cells), colonial (groups of cells), and unicellular (single cells).

### Step 3: Analyze the third statement
**Statement:** They have heterocyst, which are clear cells without chlorophyll.

**Analysis:** This statement is correct. Heterocysts are specialized cells in some cyanobacteria that are involved in nitrogen fixation. They are indeed clear and lack chlorophyll, allowing them to perform their specific function.

### Step 4: Identify the incorrect statement
Since all the analyzed statements about blue-green algae are correct, we need to conclude that there may be an implied statement that is not listed or that the question is asking for a specific incorrect detail that is not explicitly mentioned in the provided statements.

### Conclusion
Based on the analysis, all provided statements about blue-green algae are accurate. However, if the question implies that there is a statement which is incorrect, it could be a statement not included in the analysis.

### Final Answer
All of the statements provided about blue-green algae are correct.

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