What were the primary topics discussed at the earth summit in 1992? a. environmental and political issues b. environmental and development issues c. political and development issues d. world market economy and war

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 many species of living things are alive on earth today? more than 1,000,000 none of these answers are correct 100-500 1,000 –500,000 o 500,000 -1,000,000

The buildup of sediments where a river empties into a slow-moving or nonmoving body of water is known as a/an