Which of the following will have the maximum concentration of harmful chemicals in its body?
Peacock, Frog, Snake, Grasshopper

Explanation

In order to answer such questions, we should first write the food chain involving the given organisms. The organism which occurs at the highest trophic level (on the extreme right side) in the food chain will have the maximum concentration of harmful chemicals in its body. In this case, grass is eaten by grasshopper, grasshopper is eaten by frog, frog is eaten by snake by snake and finally snake is eaten by peacock. So, the food chain will be :
Grass `to` Grasshopper `to` Frog `to` Snake `to` Peacock
In this food chain, since peacock occurs at the highest trophic level (on the extreme right side), therefore, peacock will have the maximum concentration of harmful chemicals in its body.