Which group was accused of being involved in the
'Massive Plot' in Dallas?

Lee Harvey Oswald

Explanation:

In July 1962, Oswald was hired by the Leslie Welding Company in Dallas; he disliked the work and quit after three months. On October 12, he started working for the graphic-arts firm of Jaggars-Chiles-Stovall as a photoprint trainee.

yes, there are senators in each state

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.