un système est un ensemble d, element qui participent à une même complète le reste de la phrase. c, est un dm note reponse

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 is the diveristy of ecosystems natural communites and habits it is the variety of ways that species interact with each other and their environment

Babies with very low or very high birth weight are less likely to survive. observe a graph of the data.