Roundworms are different from platyhelminthes in which of the following feature/s?

Options

A. Roundworms are triploblastic
B. Roundworms have a complete digestive system
C. Roundworms have flame cells
D. All of the above

Answer

To solve the question regarding the differences between roundworms and platyhelminthes, we can break down the features mentioned in the question systematically.

### Step-by-Step Solution:

1. **Understanding Triploblastic Nature**:
- Both roundworms (Nematoda) and platyhelminthes (flatworms) are triploblastic organisms. This means they both develop from three germ layers: ectoderm, mesoderm, and endoderm.
- Therefore, the statement that "roundworms are triploblastic" does not differentiate them from platyhelminthes.

**Hint**: Remember that triploblastic organisms have three germ layers, which is a common feature in many animal phyla.

2. **Complete Digestive System**:
- Roundworms possess a complete digestive system, which means they have two openings: a mouth and an anus. This allows for a more efficient digestive process as food moves in one direction.
- In contrast, platyhelminthes have an incomplete digestive system, characterized by a single opening that serves as both the mouth and anus (a blind sac body plan).
- Thus, the presence of a complete digestive system is a key differentiating feature between roundworms and platyhelminthes.

**Hint**: Consider how the digestive systems of these organisms are structured; complete systems have two openings, while incomplete systems have only one.

3. **Presence of Flame Cells**:
- Flame cells are specialized excretory structures found in platyhelminthes, not in roundworms. They help in osmoregulation and excretion.
- Since roundworms do not have flame cells, this statement does not apply to them.

**Hint**: Identify the structures unique to each group; flame cells are a hallmark of flatworms.

4. **Conclusion**:
- The correct answer to the question is that roundworms differ from platyhelminthes in having a complete digestive system. The other options do not serve as differentiating features.

### Final Answer:
Roundworms are different from platyhelminthes in that they have a complete digestive system.