Ncert Exercises & Solutions

Q.27 Name the association in which one species produces a poisonous substance or a change in environmental conditions that is harmful to another species.

Ans. Parasitism is the association in which one species produces a poisonous substance or a change in environmental conditions that is harmful to another species. Examples are protozoans such as Amoeba and Plasmodiurm vivax that live in the human body and cause diseases.