Select the statement that is true: 1) history is best explained by eras, or time periods. 2) history need not include themes such as conflict, cooperation, industrialization - this is another social science. 3) all history is interrelated and inseparable. 4)history should only be studied as regions such as european, american, greek, etc.

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.

the graphs indicate that few people in bolivia work in industry, as that is the least expressive sector shown in the respective graphic.