Which structure would a unicellular organisms most likely have to move around? a. fins b. legs c. tentacles d. pseudopods?

d. Pseudopods. 

An example would be unicellular amoeba. 

Prokaryotes have a significant role in decomposition of organic matter, bringing back key nutrients into the trophic network. By decomposing dead plant or animal parts, they enable the circulation of elements like phosphorus and sodium.
On the other hand, specialized bacteria have a role in transforming nitrogen compounds in the soil, converting them into chemical forms that are suitable for other organisms to use.