Question

fill in the blank question
as the blastocyst digests its way into the endometrium, the outer layer of cells develops finger - like extensions which will eventually become the chorion. this outer layer of cells is called the ?

Explanation:

During implantation, the blastocyst's outer cell layer (trophoblast) invades the endometrium. It forms chorionic villi (part of the chorion). The trophoblast is crucial for embryo - maternal connection.

Answer:

trophoblast