Single-Celled __, Amoeba, Causes Bowel Issues

This page is the CodyCross answer for the clue below from Fauna and Flora, Group 173, Puzzle 5 (Retrogressive Succession).

Question is: Single-Celled __, Amoeba, Causes Bowel Issues

and the answer is: ORGANISM

Word Meaning:

ORGANISM — (biology) A discrete and complete living thing, such as animal, plant, fungus or microorganism.

Definitions from Wiktionary.

Single-celled __, amoeba, causes bowel issues — CodyCross Answer | CodyCross Solutions