It is found in the blood serum of more complex animals.

None of the group-13 elements has a major biological role in complex animals, but some are at least associated with a living being.

These are complex animals being used for a new purpose.

On earth, the trend had been toward larger and more complex animals.

"How can a highly organized, complex animal exist without a brain or nervous system?"

It suggests to us that behavior of complex animals can change very rapidly, and not always for the better.

Brachiopods begin to seem rather more complex animals than their simple shape suggests.

Efforts to engineer the pathway into more complex animals, such as sheep, have not been effective.

Well, if life has taught me anything it's this: truth is a complex animal.

More complex animals usually devote whole cells to receiving light.