From the following animal and character, mark the correct option
(a) Tapeworm – dorsoventrally flat
(b) Planaria – low regeneration capacity
(c) Ascaris – Triploblastic, acoelomate
(d) Nereis – an aquatic form , dioecious

Options

A. a–correct, b–incorrect , c–incorrect ,d–correct
B. a–correct , b–incorrect , c–incorrect , d–incorrect
C. a–correct , b–incorrect , c–correct , d–incorrect
D. a–incorrect , b –incorrect , c –incorrect , d–correct

Answer

To solve the question, we need to analyze each option given for the respective animals and their characteristics:

1. **Tapeworm – dorsoventrally flat**
- Tapeworms belong to the class Cestoda and are indeed dorsoventrally flattened. This characteristic is true.

2. **Planaria – low regeneration capacity**
- Planaria are known for their remarkable regeneration capabilities. They can regenerate lost body parts, which means this statement is false.

3. **Ascaris – Triploblastic, acoelomate**
- Ascaris is a roundworm and is actually a pseudocoelomate, not an acoelomate. It is also triploblastic, but the statement is incorrect because it misclassifies Ascaris as acoelomate.

4. **Nereis – an aquatic form, dioecious**
- Nereis, commonly known as the ragworm, is indeed an aquatic organism and is dioecious, meaning it has distinct male and female individuals. This statement is true.

Now, let's summarize the correctness of each option:
- (a) Tapeworm – correct
- (b) Planaria – incorrect
- (c) Ascaris – incorrect
- (d) Nereis – correct

Since we are asked to mark the correct option, we find that both (a) and (d) are correct. However, if we are to select only one option based on the context of the question, we will choose (d) as it is explicitly mentioned as an aquatic form and dioecious.

**Final Answer: Option (d) Nereis – an aquatic form, dioecious is correct.**