Rhizobia are bacteria that live on the roots of some plants, such as legumes like pea plants. rhizobia convert an element in the atmosphere into ammonia. identify and explain the type of relationship this represents. a) it is parasitism because the bacteria absorbs food from the pea plant. b) it is commensalism because the bacteria and pea plant don't harm each other. c) it is competition because the rhizobia and pea plant both need the limited amount of available nitrogen. d) it is mutualism because the bacteria receives carbon from the pea plant, while the plant uses the ammonia to make amino acids.