Question

use data to account for the difference in the amount of energy used by the grasses and the amount of energy available for the horses.
enter your answer in the space provided.

Explanation:

In an ecosystem, energy transfer between trophic levels (grasses as producers, horses as primary consumers) follows the 10% rule (a key concept in Biology, specifically Ecology). Grasses capture energy via photosynthesis, but much energy is lost: grasses use energy for their own metabolism (respiration, growth, maintenance), some is not consumed (e.g., roots, stems not eaten), and of what is consumed by horses, horses use energy for their own life processes (respiration, movement, digestion), so only a fraction (≈10%) of grass energy is available to horses. Data like grass biomass, energy in grass (e.g., kcal/g), energy consumed by horses, and energy used by horses (respiration, feces) would show this loss. For example, if grass has 1000 kcal, horses might only get 100 kcal (10%) because grass uses energy for itself, and horses lose energy in digestion, respiration, etc.

Answer:

In an ecosystem, energy transfer between grasses (producers) and horses (primary consumers) follows the 10% energy transfer rule (a core ecological principle in Biology). Grasses use energy for their own metabolic processes (e.g., respiration, growth, maintenance) and some grass biomass is not consumed by horses (e.g., roots, uneaten plant parts). Of the energy horses do consume from grasses, horses use energy for their own life processes (e.g., respiration, movement, digestion), so only ~10% of the energy in grasses is available to horses. For example, if grasses have 1000 kcal of energy, horses might only gain ~100 kcal, as energy is lost at each trophic level via metabolic costs, incomplete consumption, and waste (e.g., feces). Data on grass biomass, energy content of grass, energy consumed by horses, and energy used by horses (e.g., respiratory loss, fecal energy) would quantify this difference, showing most grass energy is not transferred to horses.