Question

The--------develop into embryo.​

Answer 1

Answer:

From Egg to Embryo

Explanation:

First, the zygote becomes a solid ball of cells. Then it becomes a hollow ball of cells called a blastocyst. Inside the uterus, the blastocyst implants in the wall of the uterus, where it develops into an embryo attached to a placenta and surrounded by fluid-filled membranes.