Explain how the two parts of the nervous system work together

"The nervous system has two parts, called the central nervous system and the peripheral nervous system due to their location in the body. The centralnervous system (CNS) includes the nerves in the brain and spinal cord. ... It does this by receiving signals from the brain and passing them on to the body." I hope this helps :)

Because the carnivores keep the herbivore population in check 

When scientist examine data such as historical documents, they are using the "scientific methods"