Mark odd one w.r.t. sexuality of organism

Options

A. Nereis
B. Ascaris
C. Hirudinaria
D. Wuchereria

Answer

To solve the question of identifying the odd one out with respect to the sexuality of organisms, we will analyze each option provided in the context of their reproductive systems.

### Step 1: Identify the organisms
We have four groups of organisms to consider:
1. Neris (segmented worms)
2. Escheris (large round worms)
3. Herudinidae (leeches)
4. Nematodes (roundworms)

### Step 2: Analyze the sexuality of each organism
- **Neris**: These are segmented worms that exhibit sexual dimorphism, meaning they have distinct male and female individuals. Both produce haploid gametes that undergo fertilization.

- **Escheris**: These are large round worms that are also sexually dimorphic. They have separate male and female individuals, and fertilization occurs between them.

- **Herudinidae**: Leeches are hermaphrodites, meaning that each individual possesses both male and female reproductive organs within a single body. They can produce both types of gametes.

- **Nematodes**: These organisms also show sexual dimorphism, with distinct male and female individuals. They reproduce sexually through fertilization.

### Step 3: Identify the odd one out
From the analysis:
- Neris, Escheris, and Nematodes all have separate male and female individuals (sexual dimorphism).
- Herudinidae (leeches) are hermaphrodites, meaning they do not have separate sexes but rather have both male and female reproductive organs in one individual.

### Conclusion
The odd one out with respect to sexuality of the organism is **Herudinidae** (leeches) because they are hermaphrodites, while the others are sexually dimorphic.