The temperature of the water around it. Cnidarians, like all animals except mammals and birds, are coldblooded, meaning they cannot regulate their own temperature. Their bodies have the same temperature as the environment. This is why lizards sunbathe, for example.
They have a mouth/anus and that is it.
MEDUSA
loleveryone reading this is gonna die... lol jk
polyp
Medusa
like spokes on a wheel
yes, they have bilateral symmetry
umbrella
The two body forms in the phylum Cnidarian are the polyp and medusa. Polyps are usually stationary, with a cylindrical body and tentacles surrounding a central mouth. Medusas are free-swimming and have a bell-shaped body with tentacles hanging down.
gugu
A sponge doesn't have a body temperature, because a sponge doesn't have a body. But how warm or cold you put the sponge under water or any liquid is the temperature of the sponge.
The Portuguese Man O' War is a marine cnidarian that is classified as cold-blooded. As an invertebrate, it lacks the internal physiological mechanisms to regulate its body temperature like warm-blooded animals do. Instead, its body temperature is dependent on its external environment.