Question

I created a score and when I open the dynamic parts, and some of the instruments are in different keys than they are in the score. Why?

Answer 1

because different instruments have different native keys associated to them so for all instruments to be playing in the same key  some instruments scores need to be in a different key. Example an alto saxophone is a Flat instrument if you play a C on an alto saxophone it will sound as a Flat on a piano so for the piano and saxophone to play in the sam key the score for the saxophone needs to be transposed up.

Answer 2

Scores and parts can be displayed in C or transposed, check "View" menu, available choices are "Transposed", "Concert Pitch", "Concert Tune"

Default is be "Transposed" for single parts and "Concert Pitch" for score.