Which of these is not a characteristic of life

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.

Surrounded by microtubules, located near the nucleus. (don't try to google it) (give answer only if u know)

Which best describes a gene? a. a sister chromatid b. a chromosome c. a tetrad d. a piece of a chromosome