A. If haemoglobin binds CO, it prevents the binding of O2
haemoglobin due to the competition for same binding sites.
B. Higher conc. SO2
in air can cause stiffness of flower buds.
C. Polychlorinated biphenyls are carcinogenic (cancer causing) in
humans as well as animals.
D. Certain plants, e.g. pinus, Juniparus, quercus, pyrus and vitis
can metabolise nitrogen oxides. Hence, the correct match is