Which of the following substances combines with hemoglobin in the blood to form carboxyhemoglobin?

Observe the following statements:
Statement-$I$: The carbon-containing components of photochemical smog are acrolein,methanal,and $PAN$.
Statement-$II$: The number of greenhouse gases in the list given below is $5$: $CH_4, CO_2, NO, H_2O_{(l)}, H_2O_{(g)}, O_2, O_3$.
The correct answer is:

The measured $BOD$ values for four different water samples $(A - D)$ are as follows:
$A = 3 \, ppm; B = 18 \, ppm; C = 21 \, ppm; D = 4 \, ppm.$
The water samples which can be called as highly polluted with organic wastes,are .... .

Choose the incorrect statement.

The acids responsible for acid rain are ......... .

State the measures to control environmental pollution.