Which of the following best describes the effects of an sti on emotional and social health?
a. the infected person may become trustful of romantic partners, making future relationships more difficult.
b. the infected person may lose contact with or be rejected by friends.
c. the infected person may feel encouraged by the experience and become more social.
d. all of the above

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.

List two limitations of natural selection

Name one similarity and one difference between the morphology of a brachiopod and a bivalve