Changes

==Key Stage 3=====Meaning===[[File:HarmfulSymbol.png|right|300px|thumb|The symbol for [[harmful]] [[chemical]]s.]]A substance [[harmful]] [[chemical]] is one that can cause some damage to an [[Alive|livingorganism]]. ===About Harmful Chemicals===: [[Harmful]] [[chemical]]s can make an [[organism]] ill but will not kill the [[organism]] creatures.