Karen and steve each have a sibling with sickle-cell disease. neither karen nor steve nor any of their parents have the disease, and none of them have been tested to see if they have the sickle-cell trait. based on this incomplete information, calculate the probability that if this couple has a child, the child will have sickle-cell disease.

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:

[ answer ]

foliated

[ explanation ]

foliation forms in a rock when pressure squeezes the rock together. the rock then has a design of many different color little lines. there are three types of foliated rock. the types are slate, schist, and gneiss. each type of foliated rock is different based on grain size and foliation characteristics. the lines appear when the rock has been under pressure.

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genetic variation will increase because of a new habitat and food source.

explanation: