From a structural or anatomical point of view, the nervous system is divided into two: the Central Nervous System (CNS) and the Peripheral Nervous System (SNP).
Explanation:
The human nervous system develops in the dorsal area (the back) of the embryo as a hollow nerve tube, the neural or ependymal canal. The anterior part thickens to form the brain while the rest constitutes a single nerve cord: the spinal cord, together with the brain, forms the Central Nervous System (CNS). As the embryo develops, axons grow on both sides of the midline and join with connective tissue to give rise to pairs of spinal nerves (leaving the spinal cord) and cranial nerves (leaving the brain). These nerves and their ramifications form the Peripheral Nervous System, which consists of somatic nerves, which innervate the striated (skeletal) muscles, and the autonomic nervous system, which innervates the internal organs (viscera)
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1 you run out of fuel 2 it takes a long time 3 it’s hard to get back 4 the conditions are constantly changing making it harder to predict what could happen. Look at Apollo 12 as a example
