u/Illustrious_Ice_6487

Hi everyone, I have lost almost 100lbs in under a year. I'm 25 now.
I limited my diet a lot, but I admit I did not exercise as much as I should have (I mostly did stuff like running a lot instead of doing abs or focusing on my core).
Is this mostly excess fat and lack of muscles or is it loose skin?
I know the parts on my arms are definitely loose skin, but what about my belly?
I still plan to lose 30 to 40 lbs, so I'm trying to understand my body even better.
Thanks a lot for helping and sorry for the photos!