Sickle cell disease provides an example for which principle of molecular genetics?

a. a point mutation always causes a significant change in phenotype.

b. a point mutation always causes a change to an amino acid sequence, which may affect phenotype.

c. a significant change in phenotype may cause a genetic mutation.

d. a change to one amino acid in a protein may cause a significant change in phenotype.

nevermind the answer is d.

The correct answer is D a change to one amino acid in a protein may cause a significant change in the phenotype.

Explanation:

Sickle cell anemia is caused by the replacement of 6th amino acid in the beta chain of hemoglobin that is glutamic acid by valine.

   glutamic acid is a hydrophilic amino acid that is being replaced by a hydrophobic amino acid known as valine.

   As a result the red blood cells  appear as insoluble aggregates which which ultimately result in the sickling of Red blood cells.That"s why this disease is named as sickle cell anemia.

increase soil erosion                                             reduce soil erosion

cattle grazing                                                         hydroseeding

deforestation                                                         contour plowing

                                                                                planting vegetation

plant roots basically hold the top soil

together and stop soil erosion because

in such situation top soil is not removed

during flood but cattle grazing causes

soil erosion because cattle consume the

grasses and herbs and top soil is exposed.

same situation occurs because of

deforestation, the trees and plants are cut

down to expose top soil which causes soil

erosion

i believe it would be c: tons.