In evolutionary biology, a common ancestor is allegedly a link between two varying branches or types of creatures. (Another word for these is 'missing links', since up to this point, not a single one of these common ancestors has been found in the fossil record)
Hope that helped =)
A is the correct answer and this question should be in physics not chemistry
Answer: B I think, I'll put my reasoning below.
Explanation:
It's not A because removing N2 would only shift the equation the opposite way.
It's not C and D because I don't think those affect the specific amount of each reactant/product produced. I think temperature only affects the speed at which the reaction is performed, which won't affect anything in this case.
Relative molecular mass or RMM is the answer.