It's of the opera genre.
It's hard to tell you what the texture is without writing an essay, because, as littleoldme says, there's the whole six-hour work, and then there's the overture, which itsself is in four parts - all texturally very different.
The texture, if you're not sure, is how the the various instruments and musical 'lines' fit together - thick, thin, rough, fine etc etc. You need to go back to your class notes for this, because I doubt you would have been set the question without having been given the appropriate information.