The translation for that sentence is: Who is the teacher? So you answer it with a name. Since it is a teacher you must use Mr., Ms., or Mrs. in this case, maestra is feminine so you'll need to use Señora(Mrs.) or Señorita(Ms.).
Answer:
Se refiere al color amarillento que es propio del ámbar.
Fácil- fáciles
Difícil- difíciles
The other are ok
1 me
2 you
3 them
4 they
5 them
6 us