Shawangunk grasslands national wildlife refuge has been developed from an abandoned airport to restore habitat for six species of birds that require an area rich in tall grasses. workers must continually remove trees that are beginning to invade the area as a result of

Providing immunity by injecting the body with a weakened form a pathogen is known as

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.

How does natural selection change thephenotypes within a population over time?