Coral reefs protect beaches and shorelines from damage caused by

pollution
waves
human
other organisms

If the kidney cell of a bird has 64 chromosomes how many chromosones does the sperm of this bird have

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.

Four types of motile cells in human body?