I'm struggling to understand how Kryptonian powers develop as they spend time on earthEarth.
It took Clark years to discover his powers, yet when he's fighting the two Kryptonian warriors, they appear just as strong and fast (if not more so) than he is. In the final battle, against General Zod the general has to breath the atmosphere (and get used to it) before he can match supermanSuperman.
On Krypton, neither Jor-El nor Zod have any special powers, this implies that the the the speed and strength of the two Kryptonian warriors was due to being on earthEarth. However if this is the case, then why did Zod have to expose himself to earth'sEarth's atmosphere to gain these powers and why would Clark lose his strength when he wasn't breathing Earth's atmosphere?
The answer I'm looking for explainsneeds to explain why the powers took different amounts of time to develop and which came from the atmosphere and which came from the sunSun.