25 !
how do you name a compound with more than two elements?

There are two systems of naming molecular compounds. The first uses prefixes to indicate the number of atoms of an element that are in the compound. If the substance is binary (containing only two elements), the suffix -ide is added to the second element. Thus water is dihydrogen monoxide.

d. the weight of the book

it is because according to the process , scientific inquiry is a process with many steps because each step occurs to the scientist and if you just skip a step there would be no steps to scientific inquiry.