Answer:
Honestly, I'm not even sure what the incorrect student was trying to do. The correct answer is:
( ) = the number of elements
(1)N2 and (3)H2
I think the student added the N2 and H2 to "balance" the chemical equation when instead they should have tried the balance the equation by making sure the atoms on the reactant side are equal to the atoms on the product side. You do this by multiplying the atoms on the reactant side until they equal the product side (not by adding them, as the student did).
The water cycle is one interaction between the geosphere and the cryosphere.
The answer is B. two chlorine atoms.
The chemical formula of the compound is BaCl2~