In the diploblastic animals :

Options

A. Mesoderm and mesoglea both are absent
B. Mesoderm is present but mesolea is absent
C. Mesoderm is absent but mesoglea is present
D. Mesoderm and mesoglea both are present .

Answer

To solve the question regarding diploblastic animals, we need to understand the characteristics of these organisms and evaluate the provided options.

### Step-by-Step Solution:

1. **Understanding Diploblastic Animals**:
- Diploblastic animals are those that develop from two primary germ layers: ectoderm and endoderm.
- They do not possess a mesoderm, which is the third germ layer found in triploblastic animals.

2. **Identifying the Germ Layers**:
- Ectoderm: The outer layer that forms the skin and nervous system.
- Endoderm: The inner layer that forms the digestive tract and associated organs.
- Mesoderm: The middle layer, which is absent in diploblastic animals.
- Mesoglea: A jelly-like substance found between the ectoderm and endoderm in some diploblastic animals, such as cnidarians.

3. **Evaluating the Options**:
- **Option 1**: Mesoderm and mesoglea both are absent.
- This is incorrect because mesoglea is present in diploblastic animals.
- **Option 2**: Mesoderm is present but mesoglea is absent.
- This is incorrect because diploblastic animals do not have a mesoderm.
- **Option 3**: Mesoderm is absent but mesoglea is present.
- This is correct. Diploblastic animals lack mesoderm but have mesoglea.
- **Option 4**: Mesoderm and mesoglea both are present.
- This is incorrect as diploblastic animals do not possess a mesoderm.

4. **Conclusion**:
- The correct answer is **Option 3**: Mesoderm is absent but mesoglea is present.