The central nervous system (CNS) is protected by the bones and is made up of brain and spinal cord. And, no normal microbiota is found in the CNS and the PNS. Thus, the correct options are C, and E.
The nervous system of humans is divided into two components: the central nervous system (CNS), which is made up of the brain and spinal cord, and the peripheral nervous system (PNS), which includes all the nerves outside the brain and spinal cord.
The CNS and PNS does not have normal microbiota due to the presence of blood-brain barrier in the nervous system which does not allow the movement of substances across the nervous system.
Therefore, the correct option is c and e.
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