Since the compound C6H12 reacts with Br2 to give a dibromide, that means it contains one double bond and also since it gives an aldehyde C2H4O as one of the products, the ozonolysis implies that one end of the double bond is =CHCH3 and because the other product is C4H8O, the original compound has this structure in the attachment below. The original compound is 2-hexene.
(The structure of C6H12Br2 is also in the attachment below)