<span>While the open ocean produces little in terms of biomass, it contributes a great amount to the biosphere because of its serving as a habitat for small, primary producers as well as playing a big role in geochemical cycling.</span>
Answer:Oxygen
Explanation: During cellular respiration, glucose is broken down in the presence of oxygen to form carbon dioxide, water and energy. Glucose + oxygen --> carbon dioxide + water + energy.
The balanced chemical equation for cellular respiration is C6H12O2 + 6O2 --> 6CO2+ 6H2O + Energy
I think its option b, may carry out nitrogen fixation.
The best answer to fill in the blank is "multilayered membrane."