<p>The way it was originally written would work if the comma after the word products were a semicolon or a period. However, because it is only a comma, you need the phrase most of which to make the second clause dependent and thereby cause the punctuation to be correct.
Was that sufficiently clear? Please let me know if you are still unsure and Ill try to give a better explanation.</p>
<p>Using "most of them" makes it an incomplete thought. In order to use "most of them," you would need to change the comma to a semicolon. Read the sentence fast w/ "most of which" -- it sounds correct b/c it works w/ the comma.</p>
<p>Pistix is right, you should look at dependent and independent clauses for grammar help. The comma after the products without any sort of conjuction implies a dependent clause (a clause that can't stand by itself), therefore you must use "of which" a relative pronoun instead of "them", because "them" is used as a subject- starting an independent clause.</p>
<p>im sorry, but i never really learned correct grammar..what is a independent/dependent clause? btw, do u guys know any good grammar sources to help me review?</p>
<p>Alright, a clause is defined as something with a subject and a verb. "He ran" is a clause. The "technical" name for the two types of clauses above are the main(independent) and subordinate clause(dependent). </p>
<p>The main thing to know is that a subordinate clause can't stand by itself, and a main clause can. </p>
<p>With these two types of clauses you can form 4 different types of
sentences:</p>
<p>Simple: "He ran"- one main clause</p>
<p>Compound: "He ran, and he fell"- two main clauses connected by conjuction and a comma</p>
<p>Complex: "If he runs to fast, he will fall"- the "if he runs" is the subordinate clause and the "he will fall" is the main clause. </p>
<p>Compound-Complex: "He ran into a dog, which only had three legs, and he fell"- This combines two main clauses "He ran into a dog" and "he fell" seperated by a suboordinate clause.</p>
<p>This sentence is quite simlpe. The sentence contains two independent clauses that are not combined in any manner deemed appropriate. Therefore, the sentence as a whole is a run-on. To correct the problem, add a conjuction or a prepositional phrase to tie the two clauses together. In other words, the run-on needs to be changed to one whole sentence. Another possible way to correct the sentence would be using a period/colon. </p>