By 1960, almost 90 percent of american families owned television sets, average daily television viewing time was five hours, and television had proven itself the most effective advertising medium ever invented. a. true. b. false.

b.   jim crow laws were enacted in northern states.

. political or economical policy that isolates a country from participating in international relationships. it has been suggested that the united states participates in isolationism because of its lack of involvement in particular wars or alliances.