Which of the following best describes the function of the swim bladder of the perch?

The common name for chaetognaths is

Lungfishes are likely the direct ancestors of the terrestrial vertebrates, according to recent evidence.

Schooling in fishes has been hypothesized to serve to

Echinoderms are

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.