Answer:
Assuming this is talking about the food pyramid. There is less energy at the top of the pyramid because energy burned off by the prey in this case.
Explanation:
If a predator were to kill and eat prey, the predator would have less energy than the prey did because the prey used that energy as a means of regulating body temperature and etc.
I'm pretty sure this is how it works, please feel free to correct me if you see anything wrong with this.