What hormonal change occurs after fertilization that causes the endometrial lining to remain intact so that the fertilized egg can successfully implant in it?

enhanced global partnerships and exploration capabilities may advance international preparedness for protecting the earth from catastrophic events such as some asteroid strikes, advancing collaborative research on space weather and protecting spacecraft by developing new means for space debris removal.

since there are no options posted i'll give you a few examples.

a dolphin's flipper, bird's wing, cat's leg.