Answer:
<em>The action of something or someone speeding up.</em>
Explanation:
When something speeds up, it is accelerating.
<span>The 0-19 demographic is the cohort that is the majority of the population in the US over the years. This seems to be counter-intuitive, since it is usually thought that there are typically more adults than kids, but it shows that adults are more dispersed in their ages than youth are in the country.</span>
It adopted a policy of isolationism