In this reaction, what does copper combine with? how do you know?

For reaction D, during a lab, we had to use tongs, hold a 5c m piece of copper wire in a burner flame. The question is: In reaction D, what did copper combine with? How do you know? please help me :) thank you

Copper reacted with Oxygen I know this because if ask yourself what is fire? fire is the oxidation of a substance lol The reaction is Copper+ Oxygen------>Copper Oxide