Answer: This sentence is a complex sentence, because it contains several subordinate clauses, dependent on the independent clause.
Explanation:
The independent clause in this sentence is:
My friend (...) gave me some living room furniture
subordinate clause:
(...) who has recently moved to Michigan - depends on the main clause (characterizes "the friend")
subordinate clause:
(...)to join his family - indicates why the friends moved to Michigan
subordinate clause:
(...) that I know will be used immediately - described the furniture = one that will be used immediately
