In which organism is ddt least concentrated?
a. large fish
b. small fish
c. zooplankton
d. phytoplankton

I would say D)

Explanation:Phytoplankton are the autotrophic components of the plankton community and a key part of oceans, seas and freshwater basin ecosystems. This is the least ddt and is concentrated.

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

helicase, i think thats it