Review the electron configurations of the elements in group 2, moving down from beryllium (Besto radim (ka you observe?
Select the correct answer,
Moving down the group, each element has one more electron in its highest s sublevel than the element at
Each element's electron configuration has a noble gas core with two electrons in the nexts sublevel,
Moving down the group, each element has two more electrons than the element that comes above it.
The electron configuration of radium does not follow the pattern of the other elements in group 2

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:

the answer is d. chordata

radon is correct hope this