Some animal embryos establish axes early in development.In amphibian embryos,the anterior-posterior axis is determined by the
A) location of the vegetal pole.
B) location of the animal pole.
C) point of sperm penetration.
D) location where cleavage begins.
E) position of external light shining on the embryo.

Question

Quizplus · Accepted Answer

In amphibian embryos, the anterior-posterior axis is determined by the point of sperm penetration, which establishes the dorsal-ventral axis as well.

Some Animal Embryos Establish Axes Early in Development