A student encounters an animal embryo at the eight-cell stage. The four smaller cells that comprise one hemisphere of the embryo seem to be rotated 45 degrees and to lie in the grooves between larger, underlying cells (i.e., spiral cleavage).
-This embryo may potentially develop into a(n)
A) turtle.
B) earthworm.
C) sea star.
D) fish.
E) sea urchin.

Question

Quizplus · Accepted Answer

Spiral cleavage is characteristic of protostomes, which include annelids such as earthworms. This type of cleavage is not seen in deuterostomes like sea stars, sea urchins, turtles, or fish.

A Student Encounters an Animal Embryo at the Eight-Cell Stage