What was the spark that started world war i?

What did the united states agree to do in the treaty of guadalupe hidalgo? time4learning

The service industry in the united states grew in the late 1800s. what was one effect of that growth? the number of people with jobs in factories as unskilled workers decreased. the number of people with jobs in factories as unskilled workers increased. the middle class grew as people took jobs as clerks, lawyers, and teachers. the middle class shrank as people left jobs as clerks, lawyers, and teachers.

What was one result of the spanish-american war