I need help on only the first question. Just the first question.
And NNO LINKS

Will have the greatest effect on human health. pollution in the a. troposphere b. stratosphere mesosphere d. thermosphere

Which events are correlated but do not necessarily have a causal relationship?

How does nafta affect relations between the united states and canada? a. it bans immigration between the two countries. b. it opens the borders between the two countries. c. it raises taxes on trade between the two countries. d. it allows free trade between the two countries.