The following sentence is grammatically incorrect:

Where the lack of a natural prewdatoar in Yellowstone National Park has aresulted in the overpopulation of bison, deer and elk.
1.The sentence is not complet
2.This is a run-on-sentence
3. The subject does not agree with the verb
3. It is unclear which noun the pronoun modifies.

This is a run-on-sentence.

Nope.

It is unclear which noun

the pronoun modifies

Pronouns do not modify nouns!

Pronouns take the place of nouns.

To identify if a sentence is a run-on-sentence, we need to check if it consists of two or more independent clauses that are not properly connected or punctuated. An independent clause is a group of words that can stand alone as a complete sentence.

In the given sentence, "Where the lack of a natural predator in Yellowstone National Park has resulted in the overpopulation of bison, deer, and elk", we can see that it contains only one independent clause. However, it does lack proper punctuation. To fix the run-on-sentence, we can add a comma or a conjunction to separate the different elements in the sentence.

For example, we could write:
"Where the lack of a natural predator in Yellowstone National Park has resulted in the overpopulation of bison, deer, and elk."

By adding a period or a coordinating conjunction such as "and" or "but," we can properly separate the elements in the sentence and avoid the run-on-sentence.