Which Structure is a Hollow Ball of Cells That Develops

Question

Which structure is a hollow ball of cells that develops and implants into the uterus?
A) blastocyst
B) embryo
C) zygote
D) morula

Accepted Answer

The blastocyst is a hollow ball of cells that forms from the zygote (fertilized egg) during early embryonic development. This structure implants into the uterus and ultimately develops into the embryo. The morula is an earlier stage of embryonic development, and the zygote is the initial cell formed when sperm and egg unite. Therefore, the correct answer is A) blastocyst.