The grass gets eaten by the deer, the deer gets eaten by the wolf, the wolf gets eaten by the eagle.
Taking out Something from the Food Chain
The grass is a producer. The deer is a consumer. The wolf is a secondary consumer. Last, the eagle is tertiary consumer.
The Full Food Chain
The decomposer breaks down organic matter and recycle the nutrients back into the soil.
If one of the organisms in a food chain leave or dye then the rest of the organisms from the food chain change. For example, if the wolves leave the the eagles will dye out to lack of food, the deer will overpopulate and all the grass will be eaten by the deer.
This is my full out food chain and everything I know about food chains.