A mutation in the human gene responsible for producing hemoglobin in the blood can cause a disorder known as sickle-cell anemia. The parents of children born with sickle-cell anemia usually have no systems of the disorder, but tests indicate that both parents have the mutated gene. How can this be explained?

Why are carbon dioxide concentrations expected to increase? a carbon dioxide concentrations are expected to increase, because fossil fuel burning is expected to increase b. carbon dioxide concentrations are expected to increase, because of an increase in agriculture. c. carbon dioxide concentrations are expected to increase, because more land will have to be cleared for increasing populations and agricultural use. d. all of the above select the best answer from the choices provided mark this and return save and exit next submit submit