Where does the waste material in the body come from and why does the body need to get rid of these waste materials?

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

This aquarium exhibits biotic and abiotic factors in an aquatic environment. one of the abiotic factors is

Agroup of students are walking in the park and one of them takes a picture of a pollen grain that is been blown by the wind what caption can the student use for this picture