Earth’s crust sits on top of the mantle.
t or f

The given statement is True.

Earth is primarily composed of three layers that is Crust ( outermost), mantle ( in the middle), outer core, and inner core ( innermost).

The crust is the outermost layer where we live. It is approximately 0- 60 Km thick. It’s a solid rock layer that is divided into two types:

1) Continental crust that covers the land.

2) Oceanic crust, which covers the water bodies.

The crust sits on the top of second layer that is mantle.

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: