[quote=\"P.KH\"]http://i54.tinypic.com/33copz4.jpg\">

Hi, can anyone please help with this question? The ans given is (4), but I think it should be (1). :?:
The surrounding air that enters beaker A also contains carbon dioxide that will change the limewater chalky , however the amount is minimal. In contrast most the 21% of oxygen that was in the surrounding air was converted to carbon dioxide by the mice , thus the change in beaker B was more significant.