Which one of the following kinds of animals are triploblastic

Options

A. Sponges
B. Ctenophores
C. Corals
D. Flatworms

Answer

To determine which kinds of animals are triploblastic, we need to understand what triploblastic means.

### Step-by-Step Solution:

1. **Understanding Triploblastic**:
- The term "triploblastic" refers to organisms that develop three primary germ layers during embryonic development: ectoderm, mesoderm, and endoderm.
- These layers give rise to different tissues and organs in the body.

2. **Identifying Germ Layers**:
- **Ectoderm**: The outermost layer, which forms the skin and nervous system.
- **Mesoderm**: The middle layer, which forms muscles, circulatory system, and other internal structures.
- **Endoderm**: The innermost layer, which forms the digestive tract and other internal organs.

3. **Analyzing the Options**:
- **Option 1: Sponges**: Belong to the phylum Porifera and are diploblastic (two layers: ectoderm and endoderm). Therefore, this option is incorrect.
- **Option 2: Ctenophores**: Also diploblastic organisms. Hence, this option is incorrect.
- **Option 3: Corals**: Belong to the phylum Cnidaria and are diploblastic as well. Thus, this option is incorrect.
- **Option 4: Flatworms**: They belong to the phylum Platyhelminthes and are triploblastic, having all three germ layers (ectoderm, mesoderm, and endoderm). This option is correct.

4. **Conclusion**:
- The only option that represents triploblastic animals is **Option 4: Flatworms**.

### Final Answer:
The correct answer is **Option 4: Flatworms**.