Solenocytes and nephridia are respectively found in

Options

A. Platyhelmenth and Annelids
B. Annelids and Nematoda
C. Cenidaria and Mollusac
D. Mollusca and Echinodermata

Answer

To solve the question regarding the organisms in which solenocytes and nephridia are found, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terms:**
- **Solenocytes:** These are specialized cells that are long, narrow, and flagellated. Their primary function is excretion, specifically the excretion of nitrogenous wastes.
- **Nephridia:** These are tubular excretory structures found in certain organisms. They are coiled tubes that are glandular and richly supplied with blood vessels, functioning in excretion.

2. **Identify the Phyla:**
- **Solenocytes:** These cells are primarily found in the phylum **Platyhelminthes** (flatworms). They serve as the main excretory organs in these organisms.
- **Nephridia:** These structures are characteristic of the phylum **Annelida** (segmented worms). They are present in all segments of the body and are responsible for excretion.

3. **Match the Options:**
- Now, we can look at the options provided in the question:
- A. Platyhelminthes and Annelida
- B. Annelida and Nematoda
- C. Cnidaria and Mollusca
- D. Mollusca and Echinodermata

4. **Select the Correct Answer:**
- From our identification, we see that solenocytes are found in **Platyhelminthes** and nephridia are found in **Annelida**. Therefore, the correct answer is option **A. Platyhelminthes and Annelida**.

### Final Answer:
The correct answer is **A. Platyhelminthes and Annelida**.

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