What is the correct term for changes in the elliptical shape of earth's orbit every 100,000 years?

the correct term for changes in the elliptical shape of earth's orbit every 100,000 years is

Milankovitch cycle

Explanation:

Milankovitch cycle was discovered by Mr. Milutin Milankovitch, who described that there occur changes in the earth's orbit in 3 cycles which are distinctly of different lengths.

There occurs changes in the shape of the earth's elliptical orbit from minimum to maximum and comes back to the minimum, which takes near about 100,000 years.

The tilt of the earth is about 23.5°, which changes from about 21.5° to 24.5° and gain goes back about 41,000 years approximately.

The imaginary internal axis of the earth rotates unsteadily with a period of nearly 23,000 years.

Thus, these changes occurring in the earth's elliptical shaped orbit takes place every 100,000 years and is a cycle of the Milankovitch cycle.

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.