Because the central nervous system is so important to the proper functioning of the body, the brain is protected by the and the spinal cord is protected by the .

Skull; virtebrae

Explanation:

The brain is soft tissue and bones of skull protect the brain from any external damage. The cells of brain also secrete watery fluid known as cerebral spinal fluid into the ventricles of brain that also provide cushion like protection to brain. Apart from these, the three layers of meninges also cover the brain for protection.

The spinal is also protected by three layers of membranes called as meninges. The spinal cord runs from brain through the center of bones. The bones are known as vertebrea and provide protection to spinal cord. The cerebral spinal fluid is also present for the protection of spinal cord.

The protection for brain and spinal cord is same except the skull provide protection for brain and vertebrae for spinal cord.

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.