1. The meaning doesn't change.Ex: We derive the model (by) using the Slavnov transformations, without using the Higgs mechanism. SpringerLink - Journal ArticleSentence error
We derived the model (by) using the factors.
2. Learn about however-placement here, page 28.
3. Commas matter, not phrase order; unless, that is, you're listing the electives according to preference.The electives are English, Society, Technology and Values, and Marriage and Family.4a. The 3 electives are English, Marriage(,) and Family. <the comma is optional>
4b. The electives are English, Marriage, and Family. <the comma is helpful>