The presence of which of the following is the best indicator of incomplete combustion of petrol or diesel in an automobile engine?

The relative contribution of $O_3$,$N_2O$,and $H_2O$ to global warming is in the ratio of ......

$A$ water sample has $ppm$ level concentration of the following metals: $Fe = 0.2$,$Mn = 0.05$,$Cu = 3.0$,$Zn = 5.0$. The metal that makes the water sample unsuitable for drinking is

Which of the following is a renewable resource?

Match the following:
| List-$I$ | List-$II$ |
| :--- | :--- |
| $A$. Methemoglobinemia | $I$. $1 \ ppm$ of dissolved oxygen in water |
| $B$. Kidney damage | $II$. $1000 \ ppb$ of lead in drinking water |
| $C$. Bones and teeth damage | $III$. $BOD$ of drinking water is $2 \ ppm$ |
| $D$. Growth of fish is stopped | $IV$. $2000 \ ppm$ of nitrates in drinking water |
| | $V$. $50 \ ppm$ of fluoride in drinking water |

What is the percentage contribution of $CO$ to the total atmospheric concentration due to forest fires?