If you translate it to english, you can see that "un hombre" would be bette.r
My nephew Eduardo is 47 years old. He is an extroverted man.
This is because eduardo is 47, meaning he is not "un niño" because that means a boy. Eduardo is a man, so "Una mujer" and "una niña" wouldn't work either.
El objetivo de las cuerdas en la orquesta es conocer los registros y características sonoras de los instrumentos de la familia de instrumentos de cuerdas, así como su identificacion