Match each vocabulary word with its definition.
1. nucleus
A. the process of burning in the presence of oxygen
2. solar energy
B. a nucleus surrounded by electrons
3. combustion
C. a process that splits the atom
4. atom central
D. part of an atom
5. fission
E. capacity for doing work
6. photosynthesis
F. process that plants produce sugar
7. energy
G. energy from the sun