It would most likely be the last one. Erosion is effectively the process of natural forces breaking down rock or soil, which allows it to move from place to place with the aid of forces like wind or water. I would say the answer would be the first one, but it only says rock, while erosion can affect more than just rocks. Hope this helps.
Set this up as
10 = 40 (1/2)t/28
and solve for t in years.
10/40 = (1/2)t/28
log(0.25) = (t/28) log(0.5)
t = 28 log(0.25) / log(0.5) years = 56 years
Test the answer:
56 years = 2(28 years) = 2 half-lives, so the remaining amount should be 1/2 of 1/2 of the initial amount, i.e. 1/4 of the initial amount, and 10 mg = 1/4 of 40 mg.
<span> Northwest Territories, the Yukon, and the Nunavut.
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Answer:
a bar-built estuary and a coastal plain
Explanation: