Which two energy sources can help a star maintain its internal thermal pressure?
A)nuclear fusion and gravitational contraction
B)nuclear fusion and chemical reactions
C)nuclear fission and gravitational contraction
D)nuclear fusion and nuclear fission
E)chemical reactions and gravitational contraction

Question

Quizplus · Accepted Answer

Nuclear fusion is the process by which stars produce energy by fusing hydrogen atoms together to form helium. This process generates tremendous amounts of energy and helps a star maintain its internal thermal pressure. Gravitational contraction occurs when the weight of the outer layers of a star compresses the inner layers, which generates heat and increases the internal pressure, also helping a star maintain its thermal pressure. Chemical reactions, nuclear fission, and other sources of energy cannot generate enough heat or pressure to sustain a star.

Which Two Energy Sources Can Help a Star Maintain Its