The cup like structure, in which the femur fits into the hip bone is known as Acetabulum.
the acetabulum is referred to a concave shapoed surface of the pelvis, which have a cup like groove. This groove helps in the binding of the femur head to the hip or the pelvic bone.
The round head of the femur gets fits into this cup shaped structure and forms the hip joint. The acetabulum is formed by the contribution of ischium, ilium and the pubis.
The magnitude, or extent of the force applied to an object at rest or in motion will determine the rate of the acceleration for that object.
Ecosystem and pond,
not sure though but good luck !
For much of the last quarter century, the leading theory of the driving force behind tectonic plate motions envisaged large scale convection currents in the upper mantle, which can be transmitted through the asthenosphere. So letter C. is the Answer.
