What is the name of the 18th president ?

crop rotation kepy different plants in the soil instead of once constintly. when switching out plants you have different nutrients being absorbed at different speeds and different roots growing differently therfore the spoil and water flow have to adapt and carry fresh nutrients to carry the constant changes that were going on in the soil.

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.