depends on the environment
a silver back gorilla would win easily win!
No. Polar bears are powerful carnivores, with greater strength and offensive weapons that would make a gorilla think twice about messing with.
Definitely the bear would win.
Gorilla vs Elephant? The Elephant no contest
Apart from how unlikely it is that these two species would ever meet in the wild, and putting any environmental factors aside, a polar bear could easily kill a gorilla. A polar bears weighs 2 or 3 times what a gorilla weighs. Also the bears are predators accustomed to killing other animals while the gorilla is a herbivore. The only chance a gorilla would have is to escape or use weapons such as rocks or sticks to defend itself.
Yes easily.
Depends on how you define size. A gorilla that's the same height as a human would be considerably heavier, and with that stronger.
Lion wins.
One on one, bear wins easily. Three gorillas would be even.
Sun bear is too small and would be killed. A sloth bear would be a very even match. Black bears, grizzly bears, brown bears, and polar bears would be too much for silverback gorillas.
I don't know if such a fight has ever happened or ever will, but my guess is that the polar bear would win. Both animals are very strong, but the polar bear has bigger claws and teeth.
elephants. depending on how strong they are.