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.

Hydrilla (hydrilla verticillata) is an invasive aquatic plant and one of the most serious aquatic pests in florida. hydrilla has already been introduced to hundreds of bodies of water throughout florida, hydrilla is difficult to control because it grows rapidly and survives in many different water depths and conditions. hydrilla • describe how hydrilla affects native plant and animal species. include both a biotic and an abiotic limiting factor. • suggest one biotic and one abiotic recommendation that could slow the spread of hydrilla