Among the 'DNA bookshelves' Carl looks for instructions for how to digest the sugar in an apple, and chooses 'anaerobic glycolysis'. Anaerobic glycolysis is the mitochondrial pathway for producing energy without oxygen. This is a sort of emergency back-up for periods of peak exertion. The vast majority of the time the mitochondria employ the oxygen utilizing citric acid cycle ( aka Krebs cycle or Tricarboxylic Acid Cycle).
In discussing Paul Maclean's triune brain ( a now pretty much abandoned notion) Carl says the cerebral cortex evolved in primates. All mammals have cerebral cortices, all even have neocortices where thought occurs. It is just that primates ( and cetaceans) have a lot more neocortex than most other mammals.