What makes the phosphorus cycle different from the carbon cycle?
a. phosphorus is abundant throughout the biosphere, and carbon is not.
b. unlike phosphorus, carbon can only be used once, and then the cycle stops.
c. phosphorus is not abundant in the atmosphere, it comes mostly from the land and ocean.
d. phosphorus relies on phosphorus-fixing bacteria to make it usable by plants.

What is the difference between the conducting zone and the respiratory zone of the respiratory system? the conducting zone is a series of cavities and tubes that move air to the respiratory zone where gases exchange with the bloodstream. the conducting zone exchanges gases between the lungs and the alveoli and the respiratory zone is a series of cavities and tubes that move air to the conducting zone. the conducting zone moves oxygen into the cells and the respiratory zone takes carbon dioxide away from the cells. the conducting zone moves oxygen into the bloodstream and the respiratory zone takes carbon dioxide away from the bloodstream.