Final answer:
Freud believed human behavior is mainly motivated by the psychosexual energy called Libido. The id contains our most primitive drives or urges, while the ego and superego develop to control the id.
Step-by-step explanation:
Freud believed human behavior is mainly motivated by the psychosexual energy called Libido. The unconscious id contains our most primitive drives or urges, such as hunger, thirst, and sex. It operates on the 'pleasure principle' and seeks immediate gratification. The ego and superego develop to control the id. The ego is the rational part of our personality and balances the demands of the id and superego in the context of reality.