How did tractor change the face of farming?

Tractors could turn soil, pull loads and speed harvests -- and they could do it better. More tractors meant fewer horses and mules. ... So, tractors replaced horses and mules. As a result, farmers no longer needed to raise crops to feed work animals.

Explanation:

a)scientists

explanation:

the national defense education act had two main goals. the first one was to provide personal that was oriented to defense, including scholars, engineering students and so on. the other goal was to provide financial assistance for the students who would be enrolling at colleges and universities in the 1960s.

the answer is mass marketing.