What factors contribute to american farming success?

It is  increased productivity is the main contributor to economic growth in U.S. agriculture. This data set provides estimates of productivity growth in the U.S. [ farm sector for the 1948-2009 period, and estimates of the growth and relative levels of productivity across the States for the period 1960-2004.

the answer to this question is give me a better question

c. seafloor spreading occurs.

d. crust becomes molten rock.

e. denser plates slide under lighter plates.