What are some of the environmental pollutants and their effects on health?

Contamination is a determining factor in the deterioration of the quality of life.
The quality of the air is determined by the presence or absence of various substances and their concentrations.
Lead is a very potent poison that until recently was present in gasoline and house paint.
The composition of the air determines its quality and suitability for certain activities.
a) Only statements I and II are correct.
b) Only statements II and IV are correct.
c) Only statements III and IV are correct.
d) All statements are correct.