What do all coelenterata have in common?

Coelenterates, also known as cnidarians, are a phylum of aquatic animals that includes jellyfish, corals, sea anemones, and hydras. They are characterized by the presence of stinging cells called nematocysts, which they use to capture prey and defend themselves from predators. Coelenterates also have a gastrovascular cavity, which is a digestive system that also functions as a circulatory system.

Here are some of the common characteristics of coelenterates:

* Body plan: Coelenterates have a radial body plan, meaning that their body is symmetrical around a central axis.

* Tentacles: Coelenterates have tentacles that are used to capture prey and defend themselves from predators.

* Nematocysts: Nematocysts are stinging cells that are found on the tentacles of coelenterates. They are used to inject venom into prey and predators.

* Gastrovascular cavity: The gastrovascular cavity is a digestive system that also functions as a circulatory system. It is lined with digestive cells that break down food, and it also contains circulatory fluid that transports nutrients and oxygen throughout the body.

* Reproduction: Coelenterates can reproduce both sexually and asexually. Sexual reproduction involves the release of eggs and sperm into the water, where they fertilize and develop into larvae. Asexual reproduction involves the budding of new individuals from the body of an adult.

Coelenterates are an important part of the marine ecosystem. They provide food for other animals, and they help to keep the oceans clean by filtering out plankton and other small organisms.