Why is carbonic acid a chemical change

Ireally need on this homework! if you get it right so much if not its fine < 3 ! (i have no points so sorry its only 10)i didnt mean to put it on social studies sorry!

How and why has british society changed over the last 50 years?

An externality can be created by a. people working at a production job and enjoying their work b. a production activity but not a consumption activity c. a consumption activity but not a production activity d. a production activity or a consumption activity externalities a. are always positive, and an example is flu vaccinations b. are always negative, and an example is the pollution created by trucks c. can be negative or positive. logging has a negative externality, and education has a positive externality d. can be negative or positive. a negative externality is having to go to school when you would rather go to the beach, and a positive externality is spending time with your friends