Carbon is an element essential to all living things on Earth. Which best describes how
carbon is transported in a food chain?
A Animals that eat plants consume carbon the
plants took from the air.
B Carbon that is consumed by plarts can never
be consumed by an animal.
C Humans can consume carbon directly from
the atmosphere.
D Plants consume sugars made of carbon
found in the environment.

if someone had the list of traits you provided

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.

it is a limiting nutrient limited by a single nutrient in the ecosystem, & the single goes very slow.