Answer:
The words that form the independent clause in the sentence "The movie, which we watched yesterday, was hilarious." are: The movie was hilarious.
Explanation:
There are two types of clauses:
Both types of clauses consist mainly of a subject and a verb, they are separated by commas, or they have subordinating conjunction at the beginning of the clause.
In this case, the clause between commas (which we watched yesterday) is the dependant clause. I can not fully understand the meaning of it when reading only that clause since information is missing. The clause The movie was hilarious is the independent clause because it can stand on its own.