Question Detail
Question
In humans, which structure implants into the endometrium during early pregnancy?
Correct Answer
Option B is the correct answer.
Detailed Explanation
The blastocyst, a hollow ball of cells with an inner cell mass and an outer trophoblast layer, is the developmental stage that implants into the uterine lining (endometrium).
Hint
It's the stage that 'hatches' from the zona pellucida to attach.