The Process of Implantation Is Characterized by Which of Following

The process of implantation is characterized by which of following processes? Select all that apply.

A) The trophoblast attaches itself to the surface of the endometrium.
B) The most frequent site of attachment is the lower part of the anterior uterine wall.
C) Between 7 and 10 days,the zona pellucida disappears and the blastocyst implants itself in the uterine lining.
D) The lining of the uterus thins below the implanted blastocyst.
E) The cells of the trophoblast grow down into the uterine lining,forming the chorionic villi.