Question

3.Which accidental is used in measure 15?How does this accidental alter the original note?

4.What does the dynamic marking mf mean in measure 1?
5.what do the dots above repeated notes in measure 2 mean?

Answer 1

IDK which measure 3 is, but MF means MetzoForte, or partially loud, and the dots over the notes mean to play them accented (louder & shorter)