This trophoblast helps to implant the egg to the inside of the uterus. It begins to push its way into the uterine lining. Next, the trophoblast actually pulls the egg inside of the uterine wall. This trophoblast will then occupy your blood vessels and direct your blood to the fertilized egg.
Gravity, also called gravitation, is a force that exists among all material objects in the universe. For any two objects or particles having nonzero mass, the force of gravity tends to attract them toward each other. Gravity operates on objects of all sizes, from subatomic particles to clusters of galaxies.
Gravity is the centripetal force on the satellite, pulling it toward the center of its orbit.you can say that is moving of the space station or any satellite to its earth or any near planet .this is fundamental force acts on each planet .