What would most likely happen to life on earth if the carbon cycle stopped?
life would continue unchanged.
life would cease to exist.
only plants would be affected.
only animals would be affected.

B) Life would cease to exist

If there would be no carbon cycle on the earth life would be in danger of disruption. There is a finite amount of carbon present on the earth, and carbon cycle is replacing the carbon which are being used by the living being so that it can be used again and again.

For example: Plants absorb carbon dioxide from atmosphere to conduct the process of photosynthesis which is necessary for making glucose which is require by plants for their growth.

Without Carbon dioxide plant will not be able to conduct photosynthesis plants will ultimately die creating a problem for all the living organism which are dependent on plants for oxygen for breathing.

fumikage isn't really a bird, and tsuyu does have teeth. tsuyu has a transformation quirk which still allows her to be partially human. otherwise we'd have a large frog running around. fumikage has teeth because again, he isn't a bird. his head was a quirk mixture if i'm correct.