A) altruism is more likely among nonrelatives.
B) altruism is more likely among relatives.
C) altruism should occur only in higher animals.
D) only 50% of related individuals are altruistic.

A) exactly one, to replace its own genes in the gene pool
B) two, because this equals its own genes plus additional genes to make it worth it
C) three or more, because Hamilton's rule is an inequality
D) exactly three, to replace its own genes in the gene pool most efficiently

A) recipients must be more likely to carry the altruistic allele than nonrecipients.
B) actors must be more likely to carry the altruistic allele than nonactors.
C) recipients must be unrelated to the actors.
D) nonrecipients must be more likely to carry the altruistic allele than recipients.