There were people without jobs or needed better jobs and there were cities growing in size and population.
2 Reasons they had to leave was 1. They were sold to cocasion/white owners and they had to leave, and 2. The cocasion slave owners felt that the a african americans didn't belong so they took them and beat them and stuff like that. (that is cruel man) Happy to Help! :D
Answer: B) So they can communicate their results without confusion
Explanation: There are other systems besides the metric system, though the metric is the most commonly used system. In the SI international system, all units are derived from each other, forming a unique international standard. That way, all scientists around the world, or at least most of them using the SI system, can communicate in a unique scientific "language" without confusion and misunderstanding.
That is false because a change in weather or traffic you might need to change speed
