Which of the following best describes the main way that upton sinclair gathered research for the jungle?

abraham lincoln  (february 12, 1809  – april 15, 1865) was an american statesman, politician, and lawyer who served as the 16th  president of the united states  from 1861 until  his assassination  in april 1865. lincoln led the nation through the  american civil war, its bloodiest war and its greatest moral, constitutional, and political crisis.[2][3]  he preserved the  union,  abolished slavery, strengthened the  federal government, and modernized  the u.s. economy.

john maynard keynes developed new economic theories in response to the : b) great depression of the 1930s. his theories are so important that they are known as "keynesianism". in his works he supports the idea of a government with deeper involvement and intervention to end the great depression.

the colonial period, since this was a time of mass immigration from a variety of people from europe.