Solution

Because only 10% of the energy is available in the next trophic level, "energy flow in a food chain is unidirectional." As a result, higher trophic levels contain far less energy. Because most of the energy used in photosynthesis is wasted as heat, plants are unable to utilise it. This demonstrates that energy flow in the ecosystem is one-way. Pesticides enter the food chain and then enter our bodies in one of the following ways: (i)Some pesticides are swept down into the soil or into bodies of water. (ii) Plants absorb pesticides, as well as water and minerals, from the soil. These substances are taken up by aquatic animals and plants. (iii) Because these compounds do not degrade, their concentrations rise with each trophic level. (iv) Because humans are at the top of any food chain, the highest concentration of these chemicals accumulates in our bodies, which is known as biological magnification.