Which of the following organisms is located only in the 3rd trophic level of the soil food web?
a.
bacteria
b.
fungi
c.
protozoa
d.
nematodes

The correct answer is protozoa.

Protozoans, such as amoeba and flagellates are present only at the third tropic level of soil food web which feeds on bacteria (primary consumers present on second trophic level). While, nematodes are present at both second and third trophic level, and fungi and bacteria are present in second trophic level only.

if im correct it is acid in the stomach