How necessary was an abundant labor force to prepare the fields for planting?

"if i have seen farther than others," said newton, "it is because i have stood on the shoulders of giants." who were the giants to whom newton was referring? could this be said of any scientific accomplishment? explain.

Which is true about the monroe doctrine?

Why was the sixteenth amendment important to woodrow wilson’s efforts to regulate the economy? a) the sixteenth amendment lowered interest rates charged by banks. b) the sixteenth amendment allowed congress to levy an income tax c) the sixteenth amendment lowered tariffs on imported goods d) the sixteenth amendment allowed congress to break up monopolies