One of the following is common in earthworm and cockroach

Options

A. Double solid and ventral nerve cord
B. Presence of nephridia
C. Equal body segments
D. Malpighian tubules

Answer

To determine the common feature between earthworms and cockroaches, we need to analyze the given options and identify what is shared by both organisms.

### Step-by-Step Solution:

1. **Identify the Options**: The question presents several options that describe characteristics of earthworms and cockroaches. We need to evaluate these options to find a commonality.

2. **Evaluate the First Option**: The first option mentions a "dorsal solid and ventral nerve cord."
- Both earthworms and cockroaches possess a ventral nerve cord.
- In earthworms, the nerve cord runs along the ventral side of the body and is responsible for transmitting signals throughout the organism.
- Cockroaches also have a ventral nerve cord that serves a similar function.

3. **Evaluate the Second Option**: The second option refers to "nephridia as an excretory organ."
- Nephridia are indeed present in earthworms and are part of their excretory system.
- However, cockroaches do not have nephridia; they have a different excretory system involving Malpighian tubules.

4. **Evaluate the Third Option**: The third option mentions "equal body segments."
- Earthworms have a segmented body structure, with many equal segments.
- Cockroaches, on the other hand, do not have a segmented body in the same way; their body is divided into three main parts (head, thorax, abdomen) but not into equal segments.

5. **Evaluate the Fourth Option**: The last option describes "excretory organs."
- As previously mentioned, earthworms have nephridia, while cockroaches have Malpighian tubules, indicating that this is not a common feature.

6. **Conclusion**: After evaluating all the options, the only common feature between earthworms and cockroaches is the presence of a ventral nerve cord. Therefore, the correct answer is the first option.

### Final Answer:
The common feature in both earthworms and cockroaches is the presence of a **ventral nerve cord**.

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