Cerebrum — Associated with higher brain function such as thought and action.

— Associated with regulation and coordination of movement, posture, and balance.

— Diencephalon is made up of four distinct components: the thalamus, the subthalamus, the hypothalamus, and the epithalamus. The hypothalamus is a major integral part of the endocrine system and links the nervous system to the endocrine system via the pituitary gland. The thalamus helps in relaying sensory and motor signals to the cerebral cortex, and regulating consciousness, sleep, and alertness.

Medulla Oblongata — Controls involuntary actions like breathing, heart function, blood vessel function, digestion, sneezing, and swallowing. 

Then Peripheral nervous system consists of Somatic nervous system and Autonomic nervous system.

The Autonomic nervous system consists of Sympathetic nervous system and Parasympathetic nervous system.
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Cerebrum;- largest portion of brain, helps in transferring message by nerves.
cerebellum;-it is also known as the little brain. it controls body  funtions such as balance, posture etc,..
medulla oblongata;- it is a essential portion of brain, it maintains vital body functions such as breathing and heart beat.... 
i dont know about diencephalon soo i dint answer plss mark my answer as best if u fell correct