During World War I, 116,516 US soldiers were killed and 204,002 were wounded. If you add those two numbers together, the total number of US soldiers killed or wounded was 320,518.
You can represent that as a fraction of the current population of Chicago like this:

For simplicity's sake (since I assume the Chicago population number is an estimate), let's round the number of soldiers killed or wounded down to 300,000. That would look like this:

We can simplify that down a lot by dividing the number of soldiers and the number of Chicagoans by the least common denominator of 300,000. That would give us this fraction:

So for every 1 US soldier killed or wounded in World War I, there are 10 Chicagoans living in the city today.
Answer:
Technological advancements
Explanation:
In simple words, generation gaps refers to the differences between two individuals born in different time period, usually at a difference of ten years, regarding their opinions, perceptions and life style culture.
Such gaps occurs majorly due to technological advancements which change the overall lifestyle in the community and thus results in significant differences between generations.
Lewis and Clark's achievements were extensive. It transformed North America's colonial battle for power, a particularity of the northwest Pacific. In the areas known today as Oregon and Washington, the US was reinforced.