The brain and spinal cord are wrapped in three layers of tissue known as , between which and the nervous tissue is a space filled with .

The skull protects the brain and the vertebrae protects the spinal cord. The brain and spinal cord are wrapped in three layers of connective tissue called meninges. Between the meninges and the central nervous system tissue is a space filled withcerebrospinal fluid.

The answer is atmosphere. there are four spheres of the earth: 1. geosphere (from greek word 'geo' = ground), 2. hydrosphere (from greek word 'hydro' = water), 3. biosphere (from greek word 'bio' = life), and 4. atmosphere (from greek word 'atmo' = air). a magnetosphere is a region of space around astronomical objects controlled by the magnetic field of that object. through the process of elimination, since lightning is present in the air, it can be found in the atmosphere.