In the criminal law in the United States, the definition of a given offense generally includes up to three kinds of elements: the actus reus, or guilty conduct; the mens rea, or guilty mental state; and the attendant (sometimes external) circumstances.
Zebras are herbivores and eat mostly different types of grass, but they also eat bark, herbs and shrubs. Zebras prefer full green grass that is short and near the ground.
Most fish can't eat zebra mussels because they can't crush the shells. A few fish species have specialized teeth and jaws that are strong enough to break the shells of mollusks, and some of them do eat zebra mussels. In Europe the roach, is a major predator of zebra mussels, along with bream, and silver bream.