Instinct can make organisms respond complexly to stimuli. Relatively non-instinctual responses, instinctual responses require few nerve cells. A brain with an instinctual ability must have a large number of nerve cells, and no insect's brain has this. The number of nerve cells. According to this text, we can know. ['Insect responses are generally instinctive.', 'Creatures whose brain is smaller than or equal to the insect brain can only respond instinctively.', 'Organisms with brains larger than insect brains have the ability to respond non-instinctively.', 'Organisms with advanced brains generally do not respond instinctively.']