Final answer:
Kin selection is the sacrifice of an individual's life to pass on genes to relatives. It occurs when helping close relatives increases the chances of passing on one's own genes.
Step-by-step explanation:
The sacrifice of the life of an individual so that the genes of relatives may be passed on is called kin selection. This form of natural selection occurs when helping close relatives increases the chances of passing on one's own genes to the next generation. For example, mammal parents make sacrifices to take care of their offspring, which increases the survival chances of their genetic relatives.