A.
Explanation:
There are several reasons that Carbon-12 was chosen as the standard for determining the relative mass of other atoms.
- Its abundance on earth
- Carbon-12 is a very stable isotope atom
- Its has the same number of neutrons and protons hence more ideal to use for a precise calculation of <em>amu</em> (atomic mass unit) -
The mass of an atom are based on the ¹/12 mass of Carbon-12.
<span>1 archaic : happy, pleased
2 archaic : inclined, desirous
3 a : willing
he was very fain, for the young widow was “altogether fair and lovely … ” — Amy Kelly
b : being obliged or constrained : compelled
Great Britain was fain to devote its whole energy … to the business of slaying and being slain — G. M. Trevelyan</span>
B. We fixed the hole in the fence so the dog can't get out now.
There has to be a comma after fence.
That is the best book that I ( have read )on that subject.
reason = because that event has already happend in past but its impact is still on present so it is past perfect..........
