Which of the following statements is not correct about earthworm?

Options

A. It shows metanerism and the number of segments veries from 100-120.
B. The first segment at the anterior end of the body is called as the buccal segment or peristomium.
C. The first segment is prostomium.
D. The skin of earthworm is brown due to the presence of porphyrin.

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks us to identify which statement about earthworms is not correct.

2. **Review the Options**: We need to evaluate each statement provided in the options to determine its correctness.

3. **Analyze the First Option**: The first option states that earthworms show metameres and have a number of segments that varies from 100 to 120. This is correct, as earthworms (such as *Lumbricus terrestris* and *Ferritima*) typically have around 100 to 120 segments.

4. **Analyze the Second Option**: The second option mentions that the first segment at the anterior end of the body is called the buccal segment or peristomium. This statement is also correct because the first segment is indeed called the peristomium.

5. **Analyze the Third Option**: The third option claims that the first segment is the prostomium. This statement is incorrect. The prostomium is a lobe that covers the peristomium, but it is not the first segment itself.

6. **Analyze the Fourth Option**: The last option states that the skin of the earthworm is brown due to the presence of porphyrin pigment. This is a true statement as porphyrin pigments contribute to the coloration of the earthworm's skin.

7. **Conclusion**: After analyzing all the options, we find that the third option is the incorrect statement. Therefore, the answer to the question is that the statement "the first segment is prostomium" is not correct about earthworms.

**Final Answer**: The statement that is not correct about earthworms is: "The first segment is prostomium."

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