The muscles of arthropods are attached to the outside of their exoskeletons, which are made of chitin.
a. true
b. false

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.

Hemoglobin is a proton that carries oxygen around your body what is hemoglobin made from

The structure that houses the cells genetic information.