Read the following characters carefully
(a) Organ system level of organisation
(b) Sexes are separate
(c) Internal fertilization
(d) Bilateral symmetry
(e)Pseudocoelomate
How many animals given below consists of all the characters mentioned above a , b , c , d and e ? Ascaris , Ancyclostoma , Nereis , Earthworm , Taenia , Liver fluke

Options

A. two
B. three
C. four
D. six

Answer

To solve the question, we need to analyze each of the given animals based on the characteristics mentioned:

1. **Organ system level of organization**: This means that the animal has a complex organization where cells form tissues, tissues form organs, and organs form systems.

2. **Sexes are separate**: This indicates that the species is dioecious, meaning there are distinct male and female individuals.

3. **Internal fertilization**: This means that fertilization occurs inside the female's body.

4. **Bilateral symmetry**: This means that the body can be divided into two identical halves along one plane.

5. **Pseudocoelomate**: This refers to organisms that have a body cavity (coelom) that is not completely lined by mesoderm.

Now, let's evaluate each of the given animals:

- **Ascaris**:
- Organ system level: Yes
- Sexes are separate: Yes
- Internal fertilization: Yes
- Bilateral symmetry: Yes
- Pseudocoelomate: Yes
- **Conclusion**: Fits all criteria.

- **Ancyclostoma**:
- Organ system level: Yes
- Sexes are separate: Yes
- Internal fertilization: Yes
- Bilateral symmetry: Yes
- Pseudocoelomate: Yes
- **Conclusion**: Fits all criteria.

- **Nereis**:
- Organ system level: Yes
- Sexes are separate: Yes
- Internal fertilization: No (external fertilization occurs)
- Bilateral symmetry: Yes
- Pseudocoelomate: No (it is a coelomate)
- **Conclusion**: Does not fit all criteria.

- **Earthworm**:
- Organ system level: Yes
- Sexes are separate: No (it is hermaphroditic)
- Internal fertilization: Yes
- Bilateral symmetry: Yes
- Pseudocoelomate: No (it is a coelomate)
- **Conclusion**: Does not fit all criteria.

- **Taenia**:
- Organ system level: Yes
- Sexes are separate: No (it is hermaphroditic)
- Internal fertilization: Yes
- Bilateral symmetry: Yes
- Pseudocoelomate: No (it is acoelomate)
- **Conclusion**: Does not fit all criteria.

- **Liver fluke**:
- Organ system level: Yes
- Sexes are separate: No (it is hermaphroditic)
- Internal fertilization: Yes
- Bilateral symmetry: Yes
- Pseudocoelomate: No (it is acoelomate)
- **Conclusion**: Does not fit all criteria.

After evaluating all the animals, we find that **Ascaris** and **Ancyclostoma** are the only two that fit all the criteria.

**Final Answer**: 2 animals (Ascaris and Ancyclostoma) consist of all the characters mentioned above.