By the end of a normal first trimester,the zygote has
A) only the mesoderm tissue layer.
B) recognizable human features.
C) reached its birth length.
D) no organ systems.

Question

Quizplus · Accepted Answer

By the end of the first trimester, the zygote has developed into an embryo and then a fetus, with recognizable human features such as limbs and facial structures. The other options are incorrect: the embryo develops three tissue layers (ectoderm, mesoderm, and endoderm), not just the mesoderm; it is far from its birth length; and organ systems have begun to form, though they are not fully developed.

By the End of a Normal First Trimester,the Zygote Has