Question

is this a fragment or a sentence?
the reason i agree with the argument that teenagers should have unlimited access to the internet in school.
sentence
fragment

Explanation:

A sentence must have a complete thought. Here, "The reason I agree with the argument that teenagers should have unlimited access to the internet in school" is just a statement of a reason but it doesn't express a complete action or thought. It is missing something like "is...". A fragment is a group of words that does not express a complete thought.

Answer:

Fragment