What does decomposes mean?

To decompose means to breakdown or break up. It can be used about chemical compounds. It is often used for example about materials that are wanted to breakdown, these are often called bio-degradable because they will be decomposed by natural bacteria and so disappear into the soil. On the other hand sometimes you don't want things to decompose, plastic vessels holding liquids that should not be released for example, so this type of plastic is designed not to decompose.

Decomposing can also be used for vegetable or animal tissues, after the organism is dead, this is another word for rotting.