An example of a wolf food chain might be "grass - elk - wolf" or "plants - oxen - wolf." The wolf does not have any natural predators and is at the top of its food chain as an apex predator.
The wolf is able to capture its prey easily by hunting in groups with other members of its pack; however, wolves are considered endangered and this decline in the number of number hurts their food chain. Without enough wolves, the animals that were once prey are able to multiply rapidly. These prey animals do not have any animals to hunt them, so they grow bigger and bigger, throwing off the food chain balance and Earth's biomes.