Answer:
Explanation:
Địa hình, khí hậu, sông ngòi, sự hình thành các trung tâm công nghiệp lớn, đô thị hóa
C. a delta. Because a delta is the only one of those choices to where it is formed at the mouth of a river
Answer:
The correct answer is: A) Asteroid belt.
Explanation:
All of the other events can be explained by colliding worlds in the early solar system but the asteroid belt can't. The asteroid belt originated from the primitive solar nebula as a congregation of planetesimals, which were the precursors of the protoplanets.
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.
