They eat musk oxen.
Oxen are cattle, and yes, people eat cattle.
no
They eat willows, lichens and grasses.
Oxen eat the same things as cows and cattle eat: grass, hay, grain, silage, etc. See related question below for more.
yes it can
grass
Yes they do.
Grasses, plants. They are a herbivore and eat only plants.
yes you can eat fruit.
Fruit flies eat fruit and so do humans
Wolves and rabbits do not eat fruit. Some insects, such as fruit flies, eat fruit.