Is "the” necessary in this sentence?

Question

Heat, u represents **the** dependent variable, x is **the** spatial coordinate, Pe is **the** Peclet number, Re is **the** Reynolds number

Answer 1

Yes, "the" is necessary to include. I assume the phrases in the sentence refer to specific items (ie a specific variable or spatial coordinate), rather than random ones? Using "the" signals this to the reader. Also, to just not have anything would not make sense.