Answer:
I was playing with my doll.
Answer:
no one really benefied from slavery. Southern states favored slavery more then northern states.
Explanation:
The correct answer is option D. "Companies replaced hand-operated brakes with air brakes on trains". The development of air brakes on trains was a significant improvement of railroad safety. Air brakes function much more faster than hand-operated brakes, because hand-operated brakes required that the brakemen turned the brakes in one car and jump to the next to set the brakes on, and so on.
<span>b-the invasion of Poland</span>
