A) frequent warfare limited the opportunities for cultural, scientific, and artistic innovation.
b) political upheaval and reorganisation increase cultural and scientific exchanges are crossed regions.
c) revived long distant trades spread pathogens and infections to regions that have not been previously affected by them.
d) the inventions and spread of new weapons in military tactics radically transform the global balance of power.

alliances in ww1 were different from ww2 because the entente in ww1 made up of serbia,russia,france,britan,japan and italy later america  and all allied in a sort of balance of power and too keep germany,austria-hungary,and the ottomans down. russia allied the serbians in order to exert its influence in the balkans while france allied the russians because france was still in dismay and insulted after the defeat to the germans during the unification of germany and britian allied the belgians after the germans invasion of belgium.in ww2 the alliances were in a preemptive attempt to deter any further wars into happening while germany and italy allied since they were insulted and humiliated after the previous war while also sharing a similar ideology of facsim along with japan which all 3 had a want for world domination and agreed to assist one another in the endevours 

explanation:

they are best known for the cliff pueblos found throughout arizona, new mexico, colorado and utah. and for their development of desert farming.

hope i

-lavira: )