The Following Questions Are Based on the Description Below

Multiple Choice

The following questions are based on the description below.
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 lie in the grooves between larger, underlying cells (spiral cleavage) .
-The most ancient branch point in animal phylogeny is that between having

A) radial or bilateral symmetry.
B) a well-defined head or no head.
C) diploblastic or triploblastic embryos.
D) True tissues or no tissues.
E) a body cavity or no body cavity.