The principle of superposition states that the oldest sedimentary rock units are at the bottom, and the youngest are at the top. Based on this, layer C is oldest, followed by B and A. So the full sequence of events is as follows: Layer C formed.
Answer:I
If you mean by 21st century then, having awesome medical people
Explanation:
A lot of contries don't have a lot of medical staff, but the US has hired very good medical staff.
Depending on where you were, if it was mountainous, it would be very hard, but if it was a field, it would be much easier. Regardless of where you were, it would take a while to get where you wanted to go.<span />
D) immigrants tried to blend into American culture as quickly as possible