a part of a hollow bodied animal (cnidarians) that breaks down food for the animal cause they only have 1 opening in there body.
Animal with a gut that has only one opening is the cnidarian, such as jellyfish and sea anemones. This single opening serves as both the mouth and anus for the digestion process.
Yes. It seems that males only have one anal opening.
Octopus
The mouth is only one opening into the human body.
it is the snake it is the only animal to do that!
A jellyfish
The famous animal the "Porifera", has 6 body openings.
Adult echinoderms only have one body opening. Their larvae have two.
Cnidarians.
The only animals with five legs are starfish. These live in the oceans.
Well, your anus contains the anal sphincter which, technically, is an opening of the body. So I would probably say the answer you are looking for is a sphincter muscle. Otherwise known as circular muscles