Scientists believe that the Earth's orbit gradually changes from being elliptical to being nearly circular and then back to elliptical in a period of about 100,000 years. This causes global climatic change. The more circular the Earth's orbit, the less the difference in ---magnetic force on the Earth's closest and farthest locations from the sun gravitational pull on the Earth's closest and farthest locations from the sun solar energy received at the Earth's closest and farthest locations from the sun duration of days and nights at the Earth's closest and farthest locations from the sun

  solar energy received at the Earth's closest and farthest locations from the sun

Explanation:

The largest effect on climate is due to changes in received solar radiation. Changes in gravity or magnetic field have not been shown to have any significant effect on climate. Day/night differences are due to the tilt of the earth's axis, and have nothing to do with earth's orbit eccentricity.

The more circular the Earth's orbit, the less the difference in solar energy received at the Earth's closest and farthest locations from the sun.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).