Based on the clue 'a period of silence during a radio broadcast', what is the answer?

Based on the clue 'a period is one of 4 major units of geologic time ...', what is the answer? Based on the clue 'a period of guard duty in the navy one may be 4 or...', what is the answer? Based on the clue 'a period of pregnancy or a time for the developmen...', what is the answer? Based on the clue 'a period of regulation play in the national hockey...', what is the answer? Based on the clue 'a period of the mesozoic era was named for this mo...', what is the answer? Based on the clue 'a period of time in a hockey game where one team h...', what is the answer? Based on the clue 'a permanent legislative group in congress that mee...', what is the answer? Based on the clue 'a perpetual one was tended to by the vestal virgin...', what is the answer?