Mesoglea is

Options

A. A germinal layer present between ectoderm and endoderm
B. An undifferentiated layer present between ectoderm and endoderm
C. Another name of mesoderm
D. A spongy layer of skin

Explanation

### Step-by-Step Solution:

1. **Definition of Mesoglea**: Mesoglea is defined as a layer that exists between the ectoderm and endoderm in certain animals. It is crucial to understand its role and characteristics.

2. **Nature of Mesoglea**: Mesoglea is described as an undifferentiated layer. This means that it does not have specialized cells or tissues like other layers (ectoderm and endoderm) do.

3. **Composition of Mesoglea**: It is composed of a mass of cells, which contributes to its structure and function in the organisms that possess it.

4. **Presence in Diploblastic Animals**: Mesoglea is specifically found in diploblastic animals, which are organisms that have two primary germ layers: ectoderm and endoderm. This is an important classification that helps in identifying where mesoglea is found.

5. **Evaluation of Options**:
- The first option states that mesoglea is a germinal layer present between ectoderm and endoderm. This is incorrect because mesoglea is not a germinal layer.
- The second option claims that mesoglea is an undifferentiated layer present between ectoderm and endoderm. This is correct.
- The third option suggests that mesoglea is another name for mesoderm. This is incorrect as mesoderm is a third germinal layer found in triploblastic animals.
- The fourth option describes mesoglea as a spongy layer of skin. This is also incorrect.

6. **Conclusion**: Based on the evaluation of the options, the correct answer is that mesoglea is an undifferentiated layer present between ectoderm and endoderm.