If any subcategory, section, subsection, sentence, clause, or phrase of these sections is for any reason held invalid, such decision shall not affect the validity of the remaining portions of these sections. The board hereby declares that it would have adopted these subcategories, sections, subsections, sentences, clauses, or phrases thereof irrespective of the fact that any one or more of the subcategories, sections, subsections, sentences, clauses, or phrases be declared invalid.