Body having meshwork of cell, internal cavities lined with food filtering flagellated cells and indirect development are the characteristics of phylum

Options

A. (a) Coelenterata
B. (b) Porifera
C. (c) Mollusca
D. (d) Protozoa

Answer

To solve the question regarding the characteristics of a phylum with a body having a meshwork of cells, internal cavities lined with food-filtering flagellated cells, and indirect development, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Characteristics**:
- The question describes a body with a "meshwork of cells." This indicates a simple cellular organization rather than a complex tissue structure.
- It mentions "internal cavities lined with food filtering flagellated cells." This suggests the presence of specialized cells that help in filtering food from water.
- The term "indirect development" indicates that the organism undergoes a larval stage before reaching maturity.

2. **Analyzing the Options**:
- **A. Coelenterata**: This phylum includes organisms like jellyfish and corals, which have radial symmetry and do not fit the description of having a meshwork of cells.
- **B. Porifera**: This phylum includes sponges, which are known for their simple body structure, consisting of a meshwork of cells. They have flagellated cells (choanocytes) that line their internal cavities and are known for their indirect development through a larval stage.
- **C. Mollusca**: This phylum includes more complex organisms like snails and octopuses, which do not match the characteristics described.
- **D. Protozoa**: This group consists of unicellular organisms, which do not have a multicellular meshwork structure.

3. **Identifying the Correct Answer**:
- Based on the analysis, the only phylum that matches all the characteristics mentioned in the question is **B. Porifera**. They are indeed the most primitive multicellular animals, characterized by a simple body plan and the presence of flagellated cells for feeding.

### Final Answer:
The correct answer is **B. Porifera**.