This is the gas produced as a product of photosynthesis oxygen*
Carbon dioxide
Photosynthesis
Light energy

the wires in the toaster turning red and the toast crisping and turning brown

i think the answer is c hope this

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.