(a) From the following group of organisms create a food chain which is the most advantageous for Human beings in terms of energy.(b) State the possible disadvantage if the cereal plant is growing in soil rich in pesticides.(c) Construct a food web using the organisms mentioned above."

(a) Cereal plant ---> Human being

As this food chain involves only two organisms and the least number of trophic levels, it proves to be most beneficial for human beings in terms of energy.

(b) Disadvantages of utilizing pesticides in the soil for growing cereal crops are:

(i) Chemical pesticides are very harmful to the natural antagonists to pests and make the pests pesticide-resistant.

(ii) Crops grown through chemical pesticides are also very harmful to birds feeding on them, and fishes who live in water bodies contaminated with these pesticide-containing water.

(iii) Pesticides also prove to be harmful to humans as they accumulate in humans at a higher level due to biomagnification.

(c) Cereal plant ---> goat ---> human being ---> rat ----> snake ---> hawk.