This question is about the concept of bioaccumulation, where certain harmful substances accumulate more in higher-level organisms in a food chain.

Option 1: Grasshoppers, as primary consumers, ingest the toxin when they eat grass, but they do not accumulate as much DDT as other organisms higher up in the food chain.

Option 2: Toads are secondary consumers and will accumulate more DDT than grasshoppers because they eat many grasshoppers throughout their lives. But they may not accumulate as much DDT as the organisms in higher trophic levels.

Option 3: Snakes are tertiary consumers and eat many secondary consumers such as toads throughout their lives, which makes them accumulate more DDT. That`s why this is the correct answer.

Option 4: Cattle are also primary consumers like grasshoppers, so they will not accumulate as much DDT as higher-level consumers like snakes. Even though they are larger in size than grasshoppers, bioaccumulation is about the concentration of the toxin, not the total amount.