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 will analyze each option provided and determine whether the statements about the animals are correct or incorrect.

### Step-by-Step Solution:

1. **Option (a): Tapeworm – dorsoventrally flat**
- Tapeworms belong to the phylum Platyhelminthes, which are commonly known as flatworms. They are characterized by their dorsoventrally flattened bodies. Therefore, this statement is **correct**.

2. **Option (b): Planaria – low regeneration capacity**
- Planaria, also a member of the Platyhelminthes, are known for their remarkable ability to regenerate lost body parts. They have a **high** regeneration capacity, making this statement **incorrect**.

3. **Option (c): Ascaris – Triploblastic, acoelomate**
- Ascaris is a nematode (roundworm) and is indeed triploblastic, meaning it has three germ layers: ectoderm, mesoderm, and endoderm. However, Ascaris is not acoelomate; it is classified as pseudocoelomate because it has a body cavity that is not completely lined by mesoderm. Thus, this statement is **incorrect**.

4. **Option (d): Nereis – an aquatic form, dioecious**
- Nereis is a genus of polychaete worms that live in marine environments. They are dioecious, meaning they have distinct male and female individuals. This statement is **correct**.

### Conclusion:
Based on the analysis:
- Option (a) is correct.
- Option (b) is incorrect.
- Option (c) is incorrect.
- Option (d) is correct.

Thus, the correct options are (a) and (d).

### Final Answer:
The correct options are (a) Tapeworm – dorsoventrally flat and (d) Nereis – an aquatic form, dioecious.

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