can u plz explain y this thank u any1
The answer is C.
This is because, the air in the jar contains, along with all the other components in the air, OXYGEN. This OXYGEN, i.e 21% is USED UP by the iron fillings as they react with it to form iron oxide, i.e rust, which is also hydrated.
As the oxygen is used up, water in the tube rises to replace the lost volume of the oxygen.