Ships.
Sea transportation was just right at that time as it can carry loots, spoils of war , enough fire power to conquer new colonies, and also food and necessities for sojourners ,seafaring soldiers and traders. Even exploration of unknown territories was also done with the help of sea transportation.
Answer: The Aztec Empire grew as it conquered neighboring states, but that growth came at a cost. ... During the time of Montezuma II's reign the empire was at its peak, but so was the resentment of the subject tribes. Constant rebellions were waged. Although Montezuma defeated the rebellions, they weakened the empire.
Explanation:▶CREDIT/SOURCE◀
https://www.britannica.com/summary/Decline-of-the-Aztec-Empire
"<span>the assassination of Archduke Franz Ferdinand" is thought to be the spark that lit the powder-keg </span>of war at the beginning of the 20th century. A dense web of alliances was set off from this shooting.
Some of the effects were 1 new plants were discovered
2 most of the native americans were killed
3 the lands were renamed