I'm trying to think of a type of animal, easily understood, that does not (and never has) existed, but that could feasibly exist. As most non-bilateral animals are complicated for a child, I was considering merely bilateral, and thought that it might be possible for an animal to directly photosynthesise (even if only as a partial energy source).
My guess is that there are/could be symbiotic relationships that do exhibit photosynthesis, hence the qualifier 'direct'.
