In paragraph 3, the author mentions all of the following characteristics of the sun EXCEPT
A.The photosphere is the visible layer of the sun where energy escapes into space as sunlight.
B.Nuclear fusion takes place in the sun's core and travels outwards through a number of different layers.
C.The photosphere, which is 100 km thick, has a lower temperature than the sun's outer atmosphere.
D.The sun has a magnetic core made of liquid iron that is kept in constant motion by the sun's rotation.