Because ecosystems don't change over one day, they change over a long period of time. Plus, something that happens may be because of more than just one change.
By use IUPAC nomenclature rule compound N2O3 is named as
Dinitrogen trioxide ( answer d)
Nitrogen (N2) is named before oxygen(O3) since they are arranged alphabetically. In addition the prefix Di is used infront of nitrogen since they are two nitrogen atoms while prefix tri is used infront of oxide since they are 3 oxygen atoms
Where are the following answers?
Oxidation state of Pb in PbO2 is +4.
Oxidation state of Pb in PbCl2 is +2.
Oxidation state of Pb in Pb2O is +1.
Oxidation state of Pb in Pb4O3 is +6/4.
Hence option A. PbO2 is correct.
Hope this helps, have a nice day!