Answer:
D.
Explanation:
The underground railroad was created to help escaped slaves make it to the North where they could be free.
Conditions there were favorable to emigration
Answer:
1. If Earth's gravity was just 5% stronger, the increase would warp our planet's near-perfect circlular orbit into a tighter elliptical path. Summers and winters would become a lot harsher, the intense climate change would spark widespread famine and would likely collapse the world economy.
Explanation:
That's the only one I know
One important advantage that primary soruces have over secondary sources is that primary sources offer a firsthand account of an event - b, which isn't the case with secondary sources. Although this leaves primary sources prone to being biased compared to secondary sources.