Answer:
The real and main reason was The Assassination of Archduke Francisco Ferdinand heir to the throne of Austria-Hungary in his visit in Bosnia. The Hero Gavrilo Princep killed him because he want his country to have independence.
There are also reasons like Imperialism, Nationalism, Militarism and many otherd
On Edgenuity the answer for me was: C. Distrust
Public health
Sanitation standards were created to protect the common good in particular in cities.
During the Second Industrial Revolution, many began moving to the cities. Overcrowding of people and horses created large amounts of waste and very little clean water. Disease ran rampant and sanitation systems were put into place to protect the health of people.
The Marine Corp is a separate service within the navy department. They are responsible for conducting a group of soldiers to fight in a war and also responsible for amphibious operations with the United States Navy. They are one of the best fighting forces in the world. They devote themselves to the support of naval and army operations on land, air and at sea.