Cnidarians were the first animals to have a stomach, nerves and muscles. The anemone pulls water into its stomach to give its body rigidity so its nerves and muscles can work to create behavior. All animals have inherited the same basic structure of nerves and muscles.
Cnidarian Animation: Anemone Body Plan
Next Generation Science Standards for this Video
The anemone’s body plan is basically a sac attached to the bottom with a mouth surrounded by a ring of tentacles to catch prey. This serves the anemone well, for it can catch prey coming from all sides.