Porous body, marine forms diploblastic and indirect development are the characteristics of phylum

Options

A. Coelenterata
B. Porifera
C. Mollusca
D. Protozoa

Explanation

To answer the question regarding the characteristics of the phylum that has a porous body, marine forms, diploblastic structure, and indirect development, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Characteristics**:
- The question mentions a "porous body," which indicates the presence of pores in the organism's structure.
- It specifies "marine forms," suggesting that the organisms are primarily found in marine environments.
- The term "diploblastic" indicates that the organism has two germ layers: ectoderm and endoderm.
- "Indirect development" implies that the organism undergoes a larval stage before reaching adulthood.

2. **Analyze the Options**:
- We need to consider which phylum fits all these characteristics.
- The phylum **Porifera** (sponges) is known for its porous body structure, which has openings called ostia that allow water to flow through.
- Porifera are primarily marine organisms and exhibit a diploblastic organization, where the mesoderm is absent, and a gelatinous layer called mesoglia is present between the ectoderm and endoderm.
- They also exhibit indirect development, as they produce larvae that develop into adult forms.

3. **Eliminate Other Phyla**:
- **Protozoa**: These are unicellular organisms and do not have a porous body.
- **Mollusca**: These organisms are triploblastic (having three germ layers) and do not possess a porous structure.
- **Cnidaria**: While they are diploblastic and can be marine, they do not have a porous body structure like Porifera.

4. **Conclusion**:
- Based on the characteristics provided in the question, the phylum that fits all the criteria is **Porifera**.

### Final Answer:
The characteristics of a porous body, marine forms, diploblastic structure, and indirect development are indicative of the phylum **Porifera**.