What was the significance of collisions of dust, rock, and ice during earth’s formation?
a. to modify the density of materials present on earth
b. to facilitate heat absorption from the surrounding space
c. to blow away a strong burst of particles from the first atmosphere
d. to harden materials to form different parts of earth’s layers

A. to modify the density of materials present on Earth

Explanation:

D. to harden materials to form different parts of Earth’s layers

Explanation:

im not sure, but this is the answer i would give

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation:

hello there the answer is d