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.
Answer:
1. Salts. 2. Oil reserves. 3. Gold deposits. 4. Minerals
Explanation:
- As oceans are the lifeblood of the planet they give all the natural resources that we need to live a healthy and economic life. Seafloor contains various features like volcanic vents and trenches. These vents contain massive seafloor sulfur contents.
- Also, they consist of high-value items like gold, silver deposits as these have been constantly been drilled for such precious metals. Similarly, various minerals and salt content ate known to have been found in these deposits.
- The presence of active deposits is found near the continental plate boundary. Certain SEZ special economic zones have neb thus made to help preserve the mineral and oil wealth of nations.
It would have to be Brazil
A star begins as a nebula, a large cloud of gas and dust.
So the answer is A.
Shifting cultivation<span> is an agricultural system in which plots of land are cultivated temporarily, .... parts of the Roman empire from 400 BC to around 500 AD </span>following<span> the collapse of Roman economy and industry. ... The root question posed by these and the numerous other </span>examples<span> that could be cited of simple societies that ...</span>
