What did these doctors conclude about the main cause of the outbreak of the Black Death?

Bacteria

Explanation:

Not sure which time periods doctors you are referring to, but modern day scientists have concluded that the bubonic plague, or black death was caused by a bacteria called  Yersinia pestis. This bacteria originated in asia and was spread to europe via ship and trade routes. The bacteria was carried by the lice and fleas on rats, which carried the plague onto ships and around the world.

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:

the government closely monitored its finances to avoid another financial collapse.