* Horse benefits: Hay provides the horse with essential nutrients, energy, and fiber for survival.
* Hay benefits: While hay doesn't benefit in the same way a living organism does, the horse's digestive system breaks down the hay, and the process of eating and digesting helps distribute seeds for the next generation of hay plants.
Important to note: This is a simplified example. The real relationship is more complex, and the hay plant doesn't directly "benefit" from the horse. However, the horse eating the hay is part of a larger ecosystem where the horse's actions can indirectly contribute to the hay plant's success.