And this questions please

#3) Answers:

Driving your car a few miles a week. Use a bike more often.Unplugging your computer or home appliances when they are not in use.Always use the cold water faucet, unless if its necessary.

#4) Answers:

Pollution will cause many problems to environmentEnergy usage could cause loss of natural resources like coal.

I'm pretty sure it's c. extremely gradual but not 100% sure though.