Answer:
20. <u> Camillo di Cavour</u> Worked to bring about the unification of Italy.
*I can't see the options for 21*
The study of earth, like map reading, locations on the map, countries, continents, seas/oceans/lakes, mountains/hills (best way I could explain it, sorry if it doesnt make sense)
He was the senator for Massachusetts. That is helpful.
In a long period of severe heat or cold, most of civilians had a really rough time in obtaining foods to feed their families.
Under such conditions, people will have a greater tendency toward violence as a desperate attempt to survive.
Because of this, more wars and rebellions tend to happen within long period of sever cold or heat.
Fidel Castro overthrew the Batista government
