If a deer eats grass, what percentage of energy will the deer acquire from the grass? 0.1 percent 1 percent 10 percent 100 percent

The correct answer is 10 percent.

In a food chain, only 10 percent of the energy is transferred from one trophic level to another. The grass is the producer and the deer is the primary consumer, so, when the deer eats the grass, it acquires 10 percent of the total energy of the grass. Rest energy is dissipated in the environment through the metabolic processes taking place in the grass.  

it will increase due to the time span