The number of interest groups has grown rapidly since the 1960s.

___________ balances power by keeping government accountable.

Fill in the blank(s) with the appropriate word(s).

Single-subject designs are sometimes preferable to between-subjects group comparison designs because

A) independent variables cannot be manipulated in between-subjects group comparison designs. B) single-subject designs have greater external validity. C) important information about the way individuals perform is lost when summarizing group information. D) None of the above (single-subject designs are never preferable to between-subjects designs)