Final answer:
The sentence in question is a compound sentence because it contains two main clauses joined by a coordinating conjunction 'and', with neither clause being subordinate to the other.
Step-by-step explanation:
The sentence 'Dave loves to play fetch, and his friends enjoy fetch, as well.' is a compound sentence. This is because it contains two main clauses: 'Dave loves to play fetch' and 'his friends enjoy fetch, as well', which are joined by the coordinating conjunction 'and'. These two independent clauses are equally important to the overall meaning of the sentence, and neither one is subordinate to the other. The sentence could be split into two separate sentences and still make sense, which is a key characteristic of a compound sentence.