Principal cell types present in the body wall of sponges are

Options

A. Pinacocytes,porocytes,choanocytes,amoebocytes
B. Pinacocytes,choanocytes,amoebocytes,nephrocytes
C. Choanocytes,nerve cells,amoebocytes,nephrocytes
D. Choanocytes,porocytes,nephrocytes,Amoebocytes

Answer

### Step-by-Step Solution:

1. **Identify the Question**: The question asks for the principal cell types present in the body wall of sponges, which belong to the phylum Porifera.

2. **Understand Sponge Structure**: Sponges have a simple body structure that includes various types of cells. The body wall of sponges is made up of different specialized cells that perform specific functions.

3. **List the Principal Cell Types**:
- **Pinacocytes**: These are flat cells that cover the outer surface of the sponge. They are involved in maintaining the shape of the sponge and in the movement and adhesion of cells.
- **Porocytes**: These cells are responsible for forming the pores (ostia) in the sponge's body wall. Water enters the sponge through these pores.
- **Choanocytes**: Also known as collar cells, they line the inner chambers of the sponge and are responsible for creating water currents and capturing food particles.
- **Amoebocytes**: These are mobile cells that can move around within the sponge. They play a role in digestion, nutrient transport, and the removal of waste.

4. **Eliminate Incorrect Options**:
- Nephrocytes are not found in sponges; they are excretory cells found in insects.
- Nerve cells are also not present in sponges as they lack a nervous system.

5. **Conclusion**: The principal cell types present in the body wall of sponges are:
- Pinacocytes
- Porocytes
- Choanocytes
- Amoebocytes

### Final Answer:
The principal cell types present in the body wall of sponges are Pinacocytes, Porocytes, Choanocytes, and Amoebocytes.

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