Massive main-sequence stars have shorter lifetimes than medium-mass main-sequence stars because massive main-sequence stars:
A. have unbalanced pressure-temperature thermostats.
B. accumulate greater amounts of unstable heavy elements.
C. contain more hydrogen.
D. fuse hydrogen more rapidly.
Answer:D
Massive main-sequence stars have shorter lifetimes than medium-mass main-sequence stars because massive main-sequence stars:
A. have unbalanced pressure-temperature thermostats. B. accumulate greater amounts of unstable heavy elements. C. contain more hydrogen. D. fuse hydrogen more rapidly.