Diazotrophs Maximize Nitrogenase Activity by

Multiple Choice

Diazotrophs maximize nitrogenase activity by

A) closely coupling N₂ fixation with high rates of photosynthesis.
B) fixing N₂ at times when oxygen is absent or in low concentrations.
C) producing specialized structures to protect nitrogenase from oxygen.
D) producing specialized structures or fixing N₂ at times when oxygen is absent to protect nitrogenase from oxygen.