Traits found in some or all vertebrate groups include a bony skeleton, four limbs, and an amniotic egg. Which evolved first? Which evolved next?

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.

The model illustrates a process by which a substance is taken up by a cell

Name the types of burns one can get and which structures of the integument are damaged