A researcher is looking through a microscope at a petri dish full of mouse embryos. These embryos appear as balls with no indentations along their surfaces. These embryos are MOST likely:
A)mouse gastrulas.
B)mouse blastulas.
C)mouse meristems.
D)mouse fetuses.
E)mouse colonies.

Question

Quizplus · Accepted Answer

Embryos that appear as balls with no indentations along their surfaces are in the early stages of development and are most likely blastulas. The blastula stage is the stage immediately after fertilization, where the embryo is a ball of cells with a fluid-filled cavity in the center called a blastocoel. Mouse gastrulas have started to differentiate into the three germ layers, and mouse fetuses are well beyond the blastula stage, so they would not appear as simple balls of cells under a microscope. Mouse meristems and colonies are not developmental stages in mouse embryos.

A Researcher Is Looking Through a Microscope at a Petri