99% of extant animal species are

Question

Bilaterally symmetric.

Triploblastic.

Coelomates.

Penguins.

Answer 1

You can partially reason your way through this one.

Penguins obviously do not constitute 99% of extant animal species.

Coelomate usually refers to the eucolomates (animals with a true coelom). Eucoelomates are generally bilaterally symmetric and triploblastic, but so are pseudocoelomates (e.g., rotifers and nematodes) and acoelomates (such as flatworms). So there are more bilaterally symmetric and triploblastic species than there are coelomates.

The trickier part is bilaterally symmetric versus triploblastic as the two are generally found together. I'm not sure what answer your source is looking for, but I would argue that triploblasty is found in more species that bilateral symmetry because there are some non-bilateral animals that are triploblastic (e.g., echinoderms with pentaradial symmetry).