Why do different instruments have different sound qualities?

Different sounds with the same pitch still sound different because they all have different distribution of frequencies. But this happens because of timbre and every instrument has its own timbre.

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.