Pigs, spiders, elephants, and other animals that rely solely on instinct act as they do because they lack a

a) cerebral cortex
b) brain
c) central nervous system
d) moral compass

D. Moral compass which is mostly governed by the prefrontal contex of the brain, now this is found in humans only as of the late. The Frontal Lobe of the four lobes of the cerebral cortex is responsible for the logical thinking and problem solving, as well as rationality and reasoning further involves morality. In the theory of the Triune Brain it illustrated and clustered the brain into three different types which is the: Reptilian complex (instinct), limbic system (emotion), neocortex (higher brain)