1. I know the man who you met yesterday.
"who', a relative pronoun, functions as a subordinating conjunction making the clause "who you met yesterday" a dependent clause, and the sentence a "complex" sentence.
2. I know the man who wears a red shirt.
Refer to sentence 2.
a. What is the function of "who" ?
b. Is "who wears a red shirt" a dependent or independent clause?
c. What kind of sentence is 2.?