Most likely the hippo. A hippo is very capable of killing an ox when it can flip over boats and attack humans, while hippos are much more heavier and stronger than oxen. The hippo has a wide, giant mouth that can hold on the ox's head tight and drown it in the water. If the ox tried to gore the hippo with its horns, the hippo will get mad after it got hit by the horns.
It depends on the situation of where these two animals are put in, and the size and health of each other. An attacking lion with strong swipes and powerful claws and cainines could injure or kill an ox, but the ox would try to fight back if it is cornered. An ox would run away from an attacking lion, while the lion charges to jump on its back and claw it to death. If this happens, the lion is the winner. Even if the ox has sharp horns and tough strong body with thick hooves, the lion is a faster, strong hunter that have been known to attack cape buffalos and bulls. In the case, the lion would win the fight with the ox.
A hippo is very aggressive and is much more dangerous than a moose when hippos attack and kill adult crocodiles, lions, and animals that come to drink water. Hippos can actually kill any animal that goes near them, including buffalos!
Possibly the hippo.
The crocodile could win, but would get badly injured by the ox and the cattlebeast's body.
2 gorillas are very strong and powerful enough to kill an ox, so the gorillas will definitely win.
It depends on the health and size of the two animals, and the position of where are they attacking. If the ox struck the polar bear with its head or knocked its chest, the ox would win the fight. If the polar bear swiped and clawed the ox to death, the ox would be a meal of the polar bear.
The elephant. It has thick hide to protect itself from injuries like goring. One stomp of the elephant can kill an ox.
The panther will not win since the gorilla will give a strong blow to the panther and the large ox will knock down the panther with its head. This leaves the large ox and the gorilla together in fighting. The large ox will win if it knocked the gorilla down with its head or at least gore it to death.
Most likely an ox because its hooves will crush the boar's head.
The gorilla is most likely the winner. It is likely that the small ox will not win because the panther can kill the small ox by biting or clawing it and the gorilla will throw a stone on the small ox's head. The gorilla later will beat the panther by a snap on the throat or throwing a stone.
Most likely the two lions. The sun bear will not win because the ox will kill the sun bear by hitting it with its sharp horns, and the 2 lions will claw the bear to death. 2 lions are enough to kill a fully-grown ox using their 500 pound body weights, large teeth, and thick claws to bring down the ox. If the lions avoided the ox's sharp horns and attacked on the ox's body top, the lions can win such a fight.
The ox would win if it is healthy and strong with a gore of the horns on the chest. But is likely that it would get pretty injured.
Most likely the 5 gorillas will win. After the ox fights the 10 dogs, it would be killed by the dogs. Then, the gorillas can kill the dogs easily by charging at them or grabbing and throwing sticks or stones at them.
A lion because it can defend it self better then an ox and bear. The black bear will not win when the lion can kill it with a weight advantage and teeth, and also the ox can knock its chest with its thick head. This leaves the ox and the lion fighting. A lion has sharp claws and sharp teeth, while an ox has a thick, strong body, sharp horns, strong head, and large hooves. If the lion charged at the ox, the ox can hit it with its horns and kill it.