The pressureat a fluid is at : therefore, an object influid feels upward buoyant force.

The fill in the blank can be filled sequentially by-

Bottom, Greater, and Surface of fluid.

The pressure of any fluid increases with the increase in the depth. This means   that pressure at the bottom of the fluid is greater than the pressure on the surface. Due to the pressure difference, the body inside water feels upward buoyant force.

Thus, the pressure at the bottom of a fluid is always greater than at the surface of fluid. Therefore, an object in fluid feels upward buoyant force.

i'd say that the moon rock is about 2.2 billion years old.