Music Theory Questions

[Omnitrix]

I don't know what the roman nuemerals mean. It's hard to tell if it's used for more than one thing in music, since I can't understand any of what it's talking about.

I read about how chords are made out of major and minor intervals. (although it still takes me a long time to identify them)

but how are you determining these keys? I see only 2 places where an instrument hits the C key, and it doesn't look like the start or end of a melody, so how did you determine a C major key?

I explained this on a previous page look back and you can see, I think I did that just for you.

I honestly can't tell you if hes right or wrong about what key the song is in, I haven't even nor care to listen to it. But the key of the song is not limited to the first or last note.

And you also have harmony keys which contain the same exact notes. So sometimes finding the key can be complicated but like I said you gotta know what your hearing it makes it massively easier.