A comma and a conjunction always work well but it really depends on the sentences you are combining.
Answer:
The leg of my pants.
Explanation:
This has no verbs. This guy who said "The leg of my pants" is making no points or expressing any ideas whatsoever. Hope it helps :)
An argumentative text claims that a certain opinion is the only valid opinion.
Thesaurus is the tool where you can find synonyms for a word, and even antonyms.
Although you can find synonyms in a regular dictionary as well, thesauri are better when it comes to that.