Answer:
A. Early signs of life on earth
Explanation:
The Hadean, before the Archean, is the first geologic eon of Earth. It began with the formation of the Earth about 4600 million years ago and ended 4,000 million years ago. The planet had just formed and was still very hot due to high volcanism, a partially molten surface. Some geologists labels the period before the earliest-known rocks on Earth. At the end of it much cooler surface temperature and the formation of solid rock enabled to flaurish the life.
True aka pollution from machines smoke carbon emissions etc
C. Hardness is the answer
Multiple things cause the migration of people.
Economic issues arise:
People run out of jobs and opportunities
(BIGGEST REASON)
Cultural reasons:
Forced intentional migration had occurred in the past on accounts of slavery and political instability
Safety:
More popular reason now is because of war or fights with other countries, the people want to keep their family safe so they move them or move with them
Hope this helped