Which answer is correctly punctuated?

tourists in mexico enjoy eating the rich, delicious food.
tourists in mexico enjoy eating the rich delicious food.
tourists in mexico enjoy, eating the rich delicious food.
tourists in mexico enjoy, eating the rich, delicious food.

There were several scientific processes I wanted to learn about such as, photosynthesis, diffusion, and osmosis.Run-on sentences are also called fused sentences. It has at least two parts, either one of which can stand by itself meaning; two independent clauses, but the two clauses have been smooshed together. Run-on sentences contain many ideas but they have no proper punctuation marks. Comma- splice on the other hand is different.  It is composed of a run-on sentence or two independent clause connected only by comma. In Grammar, sentence fragment is just a part of a sentence, meaning it is a group of words which has no complete thought while subject complement is an adjective, noun or a pronoun or a predicative expression that follows a linking verb.