Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Q: Platelets blood component serves both structural and molecular functions in blood clotting.

A: What blood component serves both structural and molecular functions in blood clotting?
****
Q: When a sperm penetrates the egg, it triggers the egg to complete meiosis.

A: When a sperm penetrates the egg, it triggers the egg to complete what?
****
Q: The amniotic sac, which was sitting on top of the flat embryo, envelops the embryo as it folds.

A:
What sac, which was sitting on top of the flat embryo, envelops the embryo as it folds?
****