Structures in each arm of a sea star include the gonads, the system that works the tube feet, and

The orientation of a sea star is

Walter Garstang’s hypothesis of vertebrate evolution could be described as the

What type of earthworm inhabits leaf litter and the uppermost layer of the soil?

Contrast the process of binary fission and conjugation in ciliates.

How many chambers are present in the perch heart?

Reproduction in sea squirts is

By lining up all the crayfish appendages, you would find that they possess

The fossil record of echinoderms

In the later 1800s, after Darwin proposed the theory of evolution, Zoologists believed that chordate origins were in the protostome lineage.