The main source of energy for a star as it grows in size to become a red giant is
A. hydrogen fusion in the central core.
B. helium fusion in the central core.
C. hydrogen fusion in a shell surrounding the central core.
D. gravitational contraction.
Answer:C
The main source of energy for a star as it grows in size to become a red giant is
A. hydrogen fusion in the central core. B. helium fusion in the central core. C. hydrogen fusion in a shell surrounding the central core. D. gravitational contraction.