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 will analyze the key features that distinguish these two groups of organisms.

### Step-by-Step Solution:

1. **Identify the Groups**:
- Roundworms belong to the phylum Nematoda.
- Platyhelminthes, also known as flatworms, belong to a different phylum.

**Hint**: Remember the classification of organisms into different phyla based on their characteristics.

2. **Body Structure**:
- Roundworms have a cylindrical, elongated body shape, while Platyhelminthes have a flat body structure.

**Hint**: Think about the physical appearance and shape of these organisms.

3. **Digestive System**:
- Roundworms possess a complete digestive system, which includes a mouth and an anus, allowing for a one-way digestive tract.
- Platyhelminthes have an incomplete digestive system, which typically has only one opening that serves as both mouth and anus.

**Hint**: Consider how the digestive process works in these organisms and the implications of having one or two openings.

4. **Excretory System**:
- Roundworms do not have flame cells; instead, they have a simpler excretory system that may include renette cells.
- Platyhelminthes utilize flame cells for excretion.

**Hint**: Compare the excretory systems of both groups and note the presence or absence of specific structures.

5. **Body Cavity**:
- Roundworms are pseudocoelomates, meaning they have a body cavity that is not completely lined by mesoderm.
- Platyhelminthes are acoelomates, meaning they lack a body cavity.

**Hint**: Understand the significance of body cavities in terms of organism complexity.

6. **Reproductive System**:
- Roundworms typically have separate sexes (dioecious), while many Platyhelminthes are hermaphroditic.

**Hint**: Think about how reproduction varies between these two groups.

### Conclusion:
The primary difference highlighted in the question is that roundworms have a **complete digestive system**, while Platyhelminthes have an **incomplete digestive system**. Therefore, the correct answer is the complete digestive system found in roundworms.

### Final Answer:
Roundworms are different from Platyhelminthes in having a **complete digestive system**.