How long do contractions last during the expulsion phase of labor?

Which of the following is the term for the endometrium that touches the chorionic villi?

Which stem matches the definition below? same

Identify structure 33

How far apart are contractions during the dilation phase of labor?

Which definition matches the stem below? vall- 

Polyspermy results in: 

Which stem matches the definition below? drum

Which of the following germ layers develops as cells migrate inward from the ectoderm at the primitive streak?

Which definition matches the stem below? septum