Which one of the following statements is incorrect ?

Options

A. Mesoglea is present in between ectoderm and endoderm in Obelia.
B. Asterias exhibits radial symmetry.
C. Fasciola is a pseudocoelomate animal.
D. Taenia is a triploblastic animal.

Explanation

To determine which statement is incorrect among the provided options, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Analyze the First Statement:**
- The statement claims that "mesoglia is present in between ectoderm and endoderm in Obelia."
- **Explanation:** Mesoglia is indeed an undifferentiated layer found in diploblastic organisms like Obelia, located between the ectoderm (outer layer) and endoderm (inner layer).
- **Conclusion:** This statement is **correct**.

2. **Analyze the Second Statement:**
- The statement claims that "Asterias exhibits radial symmetry."
- **Explanation:** Asterias, commonly known as the starfish, does exhibit radial symmetry, meaning it can be divided into equal halves from multiple planes through its central axis.
- **Conclusion:** This statement is **correct**.

3. **Analyze the Third Statement:**
- The statement claims that "Fasciola is a pseudosilomate animal."
- **Explanation:** Fasciola, also known as the liver fluke, belongs to the phylum Platyhelminthes and is classified as an acoelomate organism, meaning it lacks a body cavity. Pseudosilomate organisms have a false body cavity, which Fasciola does not possess.
- **Conclusion:** This statement is **incorrect**.

4. **Analyze the Fourth Statement:**
- The statement claims that "Tenia is a triploblastic animal."
- **Explanation:** Tenia, or tapeworms, are indeed triploblastic, having three germ layers: ectoderm, endoderm, and mesoderm.
- **Conclusion:** This statement is **correct**.

### Final Conclusion:
- The incorrect statement among the options is the third one: "Fasciola is a pseudosilomate animal."