Early civilisations would have been most likely to co operate about sharing natural resources because this would have been mutually beneficial to both groups. Diplomacy and agreeing trade between groups would have ensured they could both survive.
<span>SHort answer: sharing limited resources and increasing trade</span>
1876 was an important year for America because it was America's 100th anniversary of the Declaration of Independence. This signifies the unity amongst Americans which establishes a strong centripetal force.