Select the wrong statement

Options

A. isogametes are similar in structure, function and behaviour
B. Anisogametes differ either in structure, function or behaviour
C. In Oomycetes female gamete is smaller and motile, while male gamete is larger and non-motile
D. Chlamydomonas exhibits both isogamy and anisogamy and Fucus shows oogamy

Explanation

To solve the question of selecting the wrong statement from the provided options, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Analyze the First Statement:**
- **Statement:** Isogametes are similar in structure, function, and behavior.
- **Evaluation:** This statement is correct. Isogametes are indeed indistinguishable gametes that share similar characteristics in structure, function, and behavior.

**Hint:** Recall the definition of isogametes and their characteristics.

2. **Analyze the Second Statement:**
- **Statement:** An isogamete differs either in structure, function, or behavior.
- **Evaluation:** This statement is incorrect. Since isogametes are defined by their similarity, they do not differ in structure, function, or behavior.

**Hint:** Think about the meaning of "iso" in isogametes.

3. **Analyze the Third Statement:**
- **Statement:** In all Oomycetes, the female gamete is smaller and motile while the male gamete is larger and non-motile.
- **Evaluation:** This statement is incorrect. In Oomycetes, the female gamete is actually larger and non-motile, while the male gamete is smaller and motile.

**Hint:** Remember the characteristics of gametes in Oomycetes.

4. **Analyze the Fourth Statement:**
- **Statement:** Chlamydomonas exhibits both isogamy and anisogamy, and Fucus shows oogamy.
- **Evaluation:** This statement is correct. Chlamydomonas can reproduce through both isogamy and anisogamy, while Fucus is known for oogamy.

**Hint:** Consider the reproductive strategies of Chlamydomonas and Fucus.

### Conclusion:
After analyzing all the statements, we find that the third statement is the incorrect one regarding Oomycetes. Therefore, the answer to the question is:

**The wrong statement is option 3.**