What is the name of earth’s innermost layer?
a. core
b. crust
c. geosphere
d. mantle

The correct answer is option A. core.

Explanation:

The core is the innermost layer of the earth. It is a very hot, dense center of the earth that is beneath the solid mantle and crust that are cold. It is a solid ball that has about a 3485-kilometer radius.

The core of the earth is very hot regions which are said to be because of radioactive decay of different elements.

Thus, the correct answer is option A.

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genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).