Final answer:
The independent clause is 'Anyone had to pass behind the shelves,' which can stand alone as a complete sentence.
Step-by-step explanation:
The independent clause in the sentence "Anyone who needed to approach Louise had to pass behind the shelves." is "Anyone had to pass behind the shelves." This clause can stand alone as a sentence and does not rely on other clauses or phrases for its complete meaning.
The dependent clause "who needed to approach Louise" cannot stand alone and provides additional information about "anyone." It's important to note that independent clauses contain both a subject and a predicate and express a complete thought, while dependent clauses only provide additional information and cannot stand alone as a complete thought.