In the solar system, the sun is the ultimate source of the energy. From the sun the energy is trapped by the producers and when the consumers feed upon the producers then some part of the energy is transferred to the next trophic level and so on. Hence, there is a unidirectional flow of energy.Complete answer:
The green plants which are the producers make their food through the process of photosynthesis by utilizing solar radiation. The food produced by the producers is consumed by the different levels of consumers. The pyramid of the energy is drawn after taking into consideration the total quantity of the energy utilized by the trophic levels in a unit area at a particular time. It is evident from the energy flow that there is always a gradual decrease in the energy content at every successive trophic level from the producer to the top consumers. Hence the energy pyramid is always upright.Therefore, the correct answer is option A. Note:
The flow of the energy from one level to another causes almost ninety-percent loss of the energy in the form of respiration and heat and the flow of only ten percent energy has occurred. This flow of energy is always unidirectional. The energy trapped by the autotrophs moves progressively through the various trophic levels but never reverts back to its previous level. This ten percent transfer of the energy to the next trophic level was given by Lindemann. Hence this law is also known as Lindeman’s ten percent law.