Ahistorian is awarded a grant to study the effects of industrial air pollution on sugarcane farms in brazil. his research will focus on which major historical theme?

a. development and transformation of social structures
b. interactions between humans and the environment
c. development and interaction of cultures
d. creation, expansion, and interaction of political systems

the two major parties acting together and cooperating when making decisions is bipartisan

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.