Can somebody sum up what 'petty bourgeoisie' is simply?

Which of the following discoveries would be most likely to cause a scientific paradigm shift? a. the discovery of more rings around uranus b. the discovery of a new pathogenic virus transmitted by mosquitoes c. the discovery that a dormant volcano is showing signs of activity d. the discovery of a new species of salamander in the amazon rainforest e. the discovery that excess heat is radiating from the center of the earth and causing global climate change

The biggest component / ingredient of summer time smog is

10. a driver should evaluate the condition of the intended driving path as being