Differentiating trait of Ascaria is

Options

A. sexual dimorphism and rhabditiform larva
B. unisexual and digenetic parasite
C. pseudocoelom and metameric segmentation
D. hermaphrodite and pseudocoelom

Answer

### Step-by-Step Solution:

1. **Understanding Ascaria**: Ascaria, specifically Ascaris lumbricoides, is a type of parasitic roundworm that is known to infect humans. It is important to identify its key characteristics to differentiate it from other organisms.

2. **Identifying Key Traits**: The main traits of Ascaris include:
- **Lack of Metamerism**: Ascaris does not exhibit metamerism, which is the division of the body into segments.
- **Monogenetic Parasite**: Ascaris is a monogenetic parasite, meaning it completes its life cycle in a single host.
- **Sexual Dimorphism**: Ascaris exhibits sexual dimorphism, which means there are distinct male and female forms that show different characteristics.
- **Rabid Larval Form**: Ascaris has a rabid (or rabidated) larval form in its life cycle.

3. **Evaluating Options**: The question provides several options regarding the traits of Ascaris. We need to evaluate which option correctly describes its differentiating traits:
- **Option A**: Sexual dimorphism and rabid form larva is present.
- **Option B**: Unisexual and digenetic parasite.
- **Option C**: Pseudocoelom and metameric segmentation.
- **Option D**: Hermaphrodite and pseudocoelom.

4. **Correct Answer**:
- **Option A** is correct because it accurately states that Ascaris exhibits sexual dimorphism (distinct male and female forms) and has a rabid form larva in its life cycle.
- The other options are incorrect because:
- Option B incorrectly describes Ascaris as unisexual and digenetic; it is monogenetic.
- Option C incorrectly states that Ascaris has metameric segmentation; it does not.
- Option D incorrectly describes Ascaris as hermaphrodite; it is not, as it has separate sexes.

### Final Answer:
The differentiating trait of Ascaris is that it exhibits **sexual dimorphism** and has a **rabid form larva** in its life cycle (Option A).

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