Which of the following is the best indicator of SO2 pollution…………
a) Lichen
b) Bryophyte
c) Pteridophyte
d) all of these
Heavy dust can cause ……………
a) Leaf blights
b) Opening of stomata
c) Closure of stomata
d) none of these
BOD stands for…………………..
a) Biotic oxidation demand
b) Biological oxidation Demand
c) Biological oxygen demand
d) Biochemical oxygen demand
We can make useful materials from garbage by the process of;
a) Chemical reaction
b) Recycling
c) Burning
d) Degeneration
