Which of the following is the characterictic of ascaris

Options

A. absence of true coelom but presence of metamerism
B. presence of neither true coelom nor metamerism
C. presence of true coelom but absence of metamerism
D. presence of true coelom and metamerism (metamerisation)

Explanation

To answer the question regarding the characteristics of Ascaris, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Organism**: Ascaris is a type of roundworm that belongs to the phylum Aschelminthes (or Nematoda). It is important to recognize that it is a parasitic organism.

2. **Understand its Habitat**: Ascaris typically exists as an endoparasite, primarily found in the intestines of hosts, particularly in small children who may ingest its eggs from contaminated soil.

3. **Examine the Body Structure**: Ascaris is characterized by having a pseudocoelom. This means it has a body cavity (coelom) that is not fully lined by mesodermal tissue, which distinguishes it from organisms with a true coelom.

4. **Triploblastic Nature**: Ascaris is a triploblastic organism, meaning it has three germ layers: ectoderm, mesoderm, and endoderm.

5. **Absence of Metamerism**: Unlike annelids (such as earthworms), Ascaris does not exhibit metamerism, which is the segmentation of the body into repeated units or segments.

6. **Conclusion**: Based on these characteristics, the correct statement regarding Ascaris is that it has an absence of a true coelom and also lacks metamerism.

### Final Answer:
The characteristic of Ascaris is the absence of a true coelom.

---