Explanation:
* Compound Sentence: The sentence has two independent clauses connected by a comma and a coordinating conjunction (in this case, "and").
* Relative Pronoun: "Which" is the relative pronoun. It connects the dependent clause "which was very playful" to the noun "dog" in the main clause.
* Dependent Clause: "Which was very playful" modifies the noun "dog" and provides additional information about it.
* Independent Clauses: The main clause is "The dog chased the ball" and the second independent clause is "I threw it."
Other Examples:
* The man, whose car was parked nearby, waved to us. (Relative pronoun: whose)
* The house, where we used to live, is now a museum. (Relative pronoun: where)
* The book, that I bought yesterday, is very interesting. (Relative pronoun: that)