What factor contributed to chicago's rise?

In 1957, james vicary reported that subliminal messages in a movie reel ("eat popcorn") caused viewers to rush to the concessions stands. although his findings became famous, the problem is that

What is the main subject of this map? a. world war i in europe b. nazi aggression in europe c. world war ii in europe d. europe during the cold war

An object weighs 40n in air , weighs 20n when submerged jn water and 30n submerged in a liquid of unknown density .what is the density of the liquid?