Which of the following quantities is directly proportional to the gravitational pull between two objects? sum of their volumes product of their masses distance that separates them distance from their center to their surface

With the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 1.90

It is really hard for me right know

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.