If the earth's differentiation were any different, it may have affected its gravitational pull and . both of these factors were essential to creating our atmosphere.

a. heat transfer
b tempter
tectonic activity

convex lenses are thicker at the middle. rays of light that pass through the lens are brought closer together (they converge). a convex lens is a converging lens. when parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus.