Name the association in which one species produces a poisonous substance or a change in environmental conditions that is harmful to another species.
In amensalism, one species is harmed and another species is neither harmed nor benefitted (unaffected). The interspecific interaction in which neither of the interacting species benefits, while one of them is harmed, is termed amensalism. Example: Bread mould Penicillium secretes an antibiotic penicillin, a harmful substance, which kills bacteria. In this interaction, Penicillium is unaffected but the bacteria is harmed.