How can humans have a positive impact on air quality? >>> ANS::by using public transportation instead of driving a car
by moving to a large city, where air quality is better
by removing vegetation such as trees and shrubs

Objects a and b are visible in the night sky. six months later they are still visible, but object b shows less parallax than object a. which object is closer? a. a b. b c. you would need to wait another six months in order to figure this out. d. you would need to know the objects' angular diameters in order to figure this out.