Plz quick
which of these equations shows rust, fe2o3, forming when oxygen, o2, reacts with iron, fe?

2fe2o3 + 4fe → 3o2

4fe → 3o2 + 2fe2o3

3o2 + 4fe → 2fe2o3

2fe2o3 → 3o2 + 4fe

Several kinds of bears are found on earth. most bears are brown or black, but one type of bear, the polar bear, is white. what process led to this difference in fur color? explain your answer.

How many moles of air are there in a human lung with a volume of 2.4 l at stp? explain your answer

Ted and emily played a mixed doubles tennis match against jack and brenda. in the second match. ted and brenda played against jack and emily. which type of chemical reaction does the situation demonstrate?