How did the black death affect medieval europe

What would lead a historian to consider two events to have a relationship of correlation rather than causation

Concerns about the environment prompt congress to pass a $1 surcharge tax on each gallon of gasoline. which statement best describes the impact of such a tax

The political cartoon below was drawn by thomas nast in 1871: a political cartoon shows a heavy set man with a long nose and a beard in a suit and vest. he is smoking a cigar and has a menacing expression. he leans against a large box that says, in counting there is strength. on top of that box is a smaller container labeled, the ballot. dialogue under the cartoon reads, thats whats the matter. boss tweed, as long as i count the votes, what are you going to do about it? say? public domain what issue does this cartoon address?