Final answer:
Phosphorus can become locked up in rock formations, where it is released into the environment through weathering of rocks and participates in the phosphorus cycle.
Step-by-step explanation:
Among the options given, phosphorus is the element that can get locked up in rock formations. Phosphorus enters the environment primarily through the weathering of rocks, a process that releases phosphate into the soil, water, and air, thereby becoming available to organisms. Over time, phosphorus can be deposited on the ocean floor, becoming part of the sediment and potentially entering into new rock formations, which is part of the phosphorus cycle.
Nitrogen, on the other hand, mainly cycles through the atmosphere and the biosphere, with processes such as nitrogen fixation and nitrogen cycling involving the conversion of d. gaseous nitrogen into usable forms like ammonia.