There is variety of answers but I would say tools and fire. Also, being on the moon before anyone else.
There were several economic warning signs during the Hoover Administration. These included rampant government spending, many farm bankruptcies and too much credit spending. These factors were signs of economic problems to come that occurred during the Hoover administration.
<span>If the state laws had more power than federal laws the Constitution would have little to no power. Hope this helps :)</span>
One by one, the Classic cities in the southern lowlands were abandoned, and by A.D. 900, Maya civilization in that region had collapsed. The reason for this mysterious decline is unknown, though scholars have developed several competing theories. which is Maya had exhausted the environment around them to the point that it could no longer sustain a very large population. <span>Other Maya scholars argue that constant warfare among competing city-states led the complicated military, family (by marriage) and trade alliances between them to break down, along with the traditional system of dynastic power. As the stature of the holy lords diminished, their complex traditions of rituals and ceremonies dissolved into chaos. Finally, some catastrophic environmental change–like an extremely long, intense period of drought–may have wiped out the Classic Maya civilization. Drought would have hit cities like Tikal–where rainwater was necessary for drinking as well as for crop irrigation–especially hard</span>
