填空题
A. electromagnetic energy
B. electromagnetic energy travels through space
C. came from the sun
D. when a change in the nucleus of an atom takes place
E. when the sunrays are fierce
F. chemical energy is generated
填空题 Visible light that produce warmth is an example of ______.
填空题 We can use energy from the sun because ______.
填空题 The energy stored in coal ______.
填空题 ______ when electron rearrangement takes place.