"Today's medical students owe a debt to Dr. Henry Gray"
Explanation:
An independent clause is a part of a sentence that can stand alone and still be a complete sentence. A complete sentence has a subject and a verb.
In the problem, the independent clause is "Today's medical students owe a debt to Dr. Henry Gray". This is because we can take this section of the sentence out of the original and it can still make sense by itself since it has the subject ("students") and the verb ("owe").
The other part of the sentence is a dependent clause because it cannot stand alone: while it does have a verb "is", it does not have a main subject to go with that verb.
