A rat that falls ill hours after eating a novel food avoids it thereafter, from one trial, across a delay that ordinary conditioning cannot bridge. Why does taste aversion break the rules?

C. Because animals are biologically prepared for ancestral associations

Not all associations are equally learnable. Garcia's rats link taste to illness in one trial across hours, and cannot link a light to the same illness at all, so the organism arrives prepared for the pairings that mattered. That killed the idea of conditioning as a blank general-purpose mechanism.