Porifera has cellular level of organization
Coelenterates have tissue level of organization
Annelida and vertebrates have organ system level of organization ...:)

Coelentrata

Coelentrata, also known as Cnidaria, exhibit tissue level of organization. This phylum includes animals like jellyfish, corals, and sea anemones. Here's why Coelentrata fits the criteria of tissue level of organization:

Presence of Tissues
- In Coelentrata, cells are organized into distinct tissue layers that perform specific functions. For example, the epidermis and gastrodermis are two tissue layers found in these organisms.
- These tissues are made up of specialized cells that work together to carry out essential functions like digestion, reproduction, and defense.

Lack of Organ Systems
- Unlike higher levels of organization like organ systems found in vertebrates, Coelentrata do not have well-defined organ systems. Instead, they rely on the coordination of different tissue layers to carry out bodily functions.
- For example, the nerve net in jellyfish is a diffuse network of nerve cells that help in coordinating movements and responses to stimuli.

Simple Body Plan
- Coelentrata have a relatively simple body plan compared to organisms with higher levels of organization. They typically have a sac-like body with tentacles for capturing prey and defense.
- Despite their simplicity, these organisms are highly successful in their aquatic environments due to their unique adaptations.

In conclusion, Coelentrata exhibit tissue level of organization, where cells are organized into specialized tissues that work together to perform essential functions. This level of organization is characteristic of simpler organisms like jellyfish and sea anemones.