The germ layer that gives rise to the animal digestive tube and digestive organs is called:

The coelomates are the least evolved bilaterally symmetrical animals.

Earthworms show all of the following features except

Which of the following statements about hydra is false?

Molecular data confirm that cnidarians branched off from the rest of animals before ________ evolved.

Sponges are protected by _____________________________.

Collar cells are a characteristic of:

The ___________________________ gives rise to muscles, bones, and the circulatory system.

Which of the following best describes the nervous system of Hydra?

Segmentation can enhance movement and locomotion.