Questions:
1. According to Lamarck, how did new structures appear? What would happen if the structures
weren't used?

The new structures appeared as acquired traits. (For example in giraffes when the trees got taller the giraffes stretched their necks to reach the leaves.) If the structures weren’t used they would most likely stay the same or adapt to the new situation. (In the giraffe case if there were more leaves appearing closer to the bottom of the trees and the tops were growing sparse then the trait would reverse.)

The diaphragm is what i think ur talking about