Question

What is the meaning of a) harmful or poisonous substances b) best or most effective?​

Answer 1

Explanation:

destructive, harmful. 2a : having the properties or effects of poison poisonous gas. b : producing a toxic substance that causes injury or death when absorbed or ingested poisonous mushrooms also : venomous a poisonous spider. 3 : spiteful, malicious.

Answer 2

something destructive or harmful

an object of aversion or abhorrence