Like the theory of evolution, the big-bang model of the universe's formation has undergone modification and ______, but it has______ all serious challenges.

A． reconcile
B． feign
C． perplex
D． arbitrate
E． commiserate

A． setting limits to their scope of action
B． effecting results by sheer momentum
C． rivaling the state in power
D． exerting constant pressure on liberties
E． eradicating people's organizations