Lowest Trophic-Level Efficiency in Animals

Which of the following represents the LOWEST trophic-level efficiency?

Horses grazing and getting plenty of exercise in a vast, open pasture in Montana Cattle grazing and getting plenty of exercise in a vast, open pasture in Montana Cattle enclosed in feedlots and fed grains Horses housed in stalls, eating grains, and getting little exercise during the winter

Trophic-level efficiency refers to the efficiency with which energy is transferred from one trophic level to the next in an ecosystem. In this context, the lowest trophic-level efficiency would typically be associated with animals that are not utilizing their food resources effectively or are in a less natural, more energy-intensive environment.

Among the options provided, "Horses housed in stalls, eating grains, and getting little exercise during the winter" likely represents the lowest trophic-level efficiency. This is because:

1. Horses in stalls are not able to graze naturally, which is a more efficient way for them to obtain energy from grass.
2. Feeding them grains, which are energy-dense but not their natural diet, can lead to less efficient energy use compared to grazing.
3. The lack of exercise can also contribute to lower overall energy expenditure and efficiency.

In contrast, the other options involve animals grazing in pastures, which is generally a more efficient way to convert plant energy into animal energy. Cattle in feedlots may have lower efficiency than grazing cattle, but they are still likely to be more efficient than horses in stalls.