Answer:
The closest shell to the nucleus is called the "1 shell" (also called the "K shell"), followed by the "2 shell" (or "L shell"), then the "3 shell" (or "M shell"), and so on farther and farther from the nucleus.
The atomic mass is the average of the isotopes of the element meaning most averages of isotopes will not be whole numbers
the correct combo is C
We know sunlight is key factor in photosynthesis so A and D are out.
we also know plants get their bulk by breaking up co2 and using the carbon which releases oxygen as a byproduct so B is also out of the question.
