No.
No. A lioness and a polar bear would not meet because one (the lioness) lives in a hot, arid environment and the other (being the polar bear) lives in a very cold dry environment. However, if they did meet, the polar bear may be able to kill the lioness with one single swipe to the head. The lioness, on the other hand, would need other lions and lionesses in order to bring down the polar bear.
The grizzly bear can kill a lion or a lioness with swipes of those powerful, sharp claws and strong swats. A large lion and a large lioness working together might bring down the grizzly bear depending on how big is the grizzly bear. Since grizzly bears have such big size and powerful claws that could kill a large lion or large lioness, it is quite strong enough to kill both of them. In this case, the grizzly bear would kill the large lioness and the large lion, but might get wounded.
A lioness can kill a black bear because it has great hunting skills that could bring down the black bear. It may also be a draw between an experienced lioness and a male black bear. Black bears have weight advantages, but lionesses have better hunting skills. Lionesses weigh 400 pounds, while black bears weigh 600 pounds. For a brown bear or a polar bear, it is a far different story.
no
If brown bears and koalas lived on the same continent, it is entirely possible that a brown bear could kill a koala. However, given that their respective continents are half a world apart, a brown bear would not kill a koala.
it is a lion Lioness means female lion.
Yes. Polar bears are bigger, more beastly, and stronger than brown bears.
Probably the black bear.
Yes, because a lioness is stronger and larger than a cougar.
Yes, and they do prey on moose sometimes.
Yes, if the kodiak bear avoided the moose's hooves and antlers (if it is a bull moose). Even a grizzly bear or an alaskan brown bear could kill a bull moose, but not when it is on the rut.
Possibly the lioness, but a lioness would only hunt a gorilla down if their are no other prey to kill.