The tests used to determine whether brain stem death has occurred are outlined below: 1  A torch is shone into both eyes to see if they react to the light. 2  The cornea (transparent outer layer of the eye), which is usually very sensitive, is stroked with a tissue or piece of cotton wool to see if the eye reacts.
The inner core extends another 900 miles inward towards the center of the Earth. It is believed that this inner core is a solid ball of mostly iron, and nickel. The mantle is made of much denser, thicker material, because of this the plates float on it like oil floats on water.
1 The mantle is made up of semi-molten rock called magma. 2  In the upper parts of the mantle the rock is hard, but lower down the rock is soft and beginning to melt. 3  The crust is the outer layer of the earth. 4  It is a thin layer between 0-60 km thick.he Earth is made up of four distinct layers: 1  The inner core is in the centre and is the hottest part of the Earth. 2  It is solid and made up of iron and nickel with temperatures of up to 5,500Â°C. 3  With its immense heat energy, the inner core is like the engine room of the Earth.