The blank is a structure in a cell that contains information that controls a cells function

The nucleus

Explanation:

The nucleus controls the metabolic functions of the cell by producing mRNA which encodes for enzymes e.g. insulin. The nucleus controls the structure of the cell by transcribing DNA which encodes for structural proteins such as actin and keratin.

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !