I believe you are asking about the amount of energy that is tranfered through the grass to the coyote. Coyotes dont eat grass so there must be other animals that must first eat the grass, then the coyote eats that animal. For example, lets say the grass has 1,000 units of enerhy that can be used for bodily functions such as homeostasis. So lets say a rabit ate some grass, the rabbit received 1,000 units of energy. But if the coyote were to eat that rabbit, he would only receive 100 units of energy because the rabbit used it for bodily functions. So it basically goes
1000
↓
100
↓
10
↓
1
I hope this helps in any way :)