Among pollutants which has the most lasting effect

Pollutants having most lasting effects are

Among various leaf factors, such as leaf age, leaf angle and leaf orientation, which has the most prominent effect on photosynthesis?

Name one pollutant which has secondary effect of 'Acid rain'

TLV values of four pollutants A,B,C and D are 2ppm, 9 ppm, 20 ppm and 50 ppm. Among these four pollutants which one is the most toxic pollutant ?

TLV value of four pollutants A, B C and D are 2ppm, 9 ppm, 20 ppm and 50 ppm. Among these four pollutants which one is the most toxic pollutant? Why ?

TLV values of four pollutants A, B, C and D are 2 ppm, 9 ppm, 20 ppm and 50 ppm. Among these four pollutants which one is the most toxic pollutant ? Why?

Among the following bonds which has the most polar character :