Answer:
a. Columbian Exchange
Explanation:
The first Europeans that managed to get tot he New World discovered lot of things that can be used back in their homelands. Lot of new crops were discovered, animals, vast fertile lands, as well as gold and silver. Once these things were introduced back in Europe the word quickly spread out, so the interest for exploration skyrocketed. Lot of people wanted to get out of Europe and go into the New World in order to get to this things, start a new life, and get rich. This resulted in countless explorations and mass migrations toward the New World.
Answer:
checks and balances. I believe that is what you want
Explanation:
counterbalancing influences by which an organization or system is regulated, typically those ensuring that political power is not concentrated in the hands of individuals or groups.
Geta was one. another one is Caracalla.
<span>They used flooded rivers for crops for rich silt left behind</span>