There is no diagram or image attached. However, from the question, it is easy to deduce that the subject is about Trophic Levels and Energy Transfer.
Please see the attached image.
According to the science of Energy Transfer, the amount of energy available at each successive level of the food chain or food pyramid, or trophic level becomes smaller and smaller relative to the energy level available in the preceding level.
As seen in the image to the left, the sun which is a natural source of energy contains an abundant amount of energy. The plant is a primary producer because it produces food directly from the sun and hence has at its disposal an abundant amount of energy.
Mice are an omnivore (that is, they eat both plants (such as wheat) and animals such as grasshoppers) hence it can be found at the two levels above the plant's trophic level. This means that they can be primary or secondary depending on what they are feeding on at the time.
So in its relationship with the wheat, the mouse is a secondary consumer. Because energy is lost as one travels up the trophic level, the amount of energy available to mice at that level is way lower than the amount available to the wheat.
Learn more about Tropic Levels here:
