Schizocoelomates and enterocoelomates are

Options

A. Acoelomates
B. True coelomates
C. Vertebrates
D. Echinoderms only

Explanation

### Step-by-Step Solution:

1. **Understanding Coelom**:
- Coelom refers to a fluid-filled body cavity that is completely surrounded by mesoderm tissue. It plays a crucial role in the organization of the body and the development of various organ systems.

2. **Types of Coelomates**:
- Animals with a true coelom are classified as coelomates. Among coelomates, there are two primary types: schizocoelomates and enterocoelomates.

3. **Schizocoelomates**:
- Schizocoelomates are organisms in which the coelom forms from the splitting of the mesoderm. This means that during embryonic development, the mesodermal layer divides to create the coelomic cavity. Examples of schizocoelomates include annelids (like earthworms) and arthropods (like insects).

4. **Enterocoelomates**:
- Enterocoelomates, on the other hand, are organisms where the coelom develops from the outpocketing of the endoderm. In this case, the coelomic cavity forms as a result of the endoderm folding and creating pouches. Examples of enterocoelomates include echinoderms (like starfish) and chordates (like vertebrates).

5. **Conclusion**:
- In summary, both schizocoelomates and enterocoelomates are types of true coelomates, differentiated by their developmental processes. Schizocoelomates arise from mesodermal splitting, while enterocoelomates arise from endodermal outpocketing.