# Why does the level of pesticide in an animal increase as the tophic level increases?

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suppose a pesticide P is sprayed on grass to kill mosquitoes. When the grasshopper and other herbivorous animals eat the grass , the concentration of P increases by the no. of grasses eaten by the grasshopper. if the amount of P in 1 grass is x and the grasshopper eats 20 grasses then the amount of P in the grasshopper will be 20x. Now, if 1 rabbit eats up 15 grasshoppers in one day then the amount of pesticide in 1 rabbit will be 20*15x = 300x. Thus, the concentration of P in an animal belonging to a higher trophic level will be in a critical level. Therefore, P which did not kill an organism in a lower trophic level can kill organisms in higher trophic levels. This phenomenon is termed as biomagnification