After a heart attack, the heart's ability to pump is lessened. this is because

Use this diagram of an animal cell to answer the question. where does the first stage of cellular respiration occur? w x y z

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.

2. which is the last step in the scientific method?