Answer: Orcas, Polar Bears, Humans, it complicated
Explanation:
It's a hard question to answer because there is going to be all sorts of technicalities, like whales or sharks, and many other species in the ocean or in Antartica. But since humans are one of the smartest living things in the world, along with again more technicalities, it just is theoretical that humans are on the top of the food chain. Because we still are discovering new species and things all over the world.