Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Coma ?
    ### Response:
    A coma is a deep state of unconsciousness. An individual in a coma is alive but unable to move or respond to his or her environment. Coma may occur as a complication of an underlying illness, or as a result of injuries, such as brain injury.    A coma rarely lasts more than 2 to 4 weeks.
    