The best piece of evidence to support the argument for kin selection as a mechanism for the evolution of altruistic behavior is:
a penguin protects its chick from seagulls.
This action demonstrates a parent-offspring relationship, which is a key aspect of kin selection. Kin selection theory posits that individuals may act altruistically toward their relatives to enhance the survival and reproduction of shared genes. In this case, the penguin's protective behavior toward its chick directly supports its own genetic lineage.