poison(A substance which, when ingested, inhaled, or absorbed, or when applied to, injected into, or developed within the body, in relatively small amounts, may cause injury, harm, or destruction to organs, tissue, or life)
polar ecosystem(The interacting systems of the biological communities and their nonliving environmental surroundings located in the regions where the air temperature is perennially below 10° Celsius, usually at and near the North and South Poles)