The moist riverbank where a fern lives is the fern's . climate
niche
habitat
community

habitat

Explanation:

the calvin cycle has three stages. in stage 1, the enzyme rubisco incorporates carbon dioxide into an organic molecule. in stage 2, the organic molecule is reduced. in stage 3, rubp, the molecule that starts the cycle, is regenerated so that the cycle can continue

i think the answer is a.keratin is the pigment responsible for skin color.