When do trophoblasts do after the blastocyst attaches to the uterine wall?
A - They do all of these
B - They invade deeper into the uterine wall
C - They encounter and surround maternal blood vessels
D - They divide and multiply in number
E - They form the chorionic villi
Answer: A - They do all of these
As the blastocyst implants, the trophoblasts that make up the outer layer of cells multiply in number and invade deeper into the uterine wall