Okay, so I have finals tomorrow and I'm sure this question is going to be on it.
"what characteristics define an animal?"
I know they're multi-cellular and lack cell walls and are motile or sessile. But what else?
To classify animals is it...
Porifera, cnidarians, platyhelminthes, nemotada, mollusca, annelida, echinoderm, anthropods, chordata.
Or am I totally wrong?
Animals are multicellular eukaryotic heterotrophs. They are capable of movement and sexual reproduction and they have diploid cells with no cell wall.
thanks honeybee. : D