What makes up muscle tissue
A organs
B cells
C organisms
D organ Systems

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.

Which statement correctly describes a way that mutations increase the likelihood that a species will survive in a changing environment

Why was mendel's work not accepted at the time? o a. his results were false. o b. he did not repeat his experiments. o c. he did not have any data. o d. his results were surprising,