Earth is spherical, but not perfect. The earth bulges at the equator due to the spinning of earth on its axis. The earth is called an oblate spheroid. The best evidence for earths shape is from satellite photographs b. The earths shadow on the moon is curved c.
Gravity is relatively constant around the earth s surface.
It is however stronger at the poles due to the polar circumference being less than the equatorial circumference. The Earths layers or spheres 1. The earth is composed of layers arranged due to density and held together by gravity a. The atmosphere begins at the earth s surface. It has no definitive end point with space.