Answer:
The ecosystem will fall out of balance.
Explanation:
The ecosystem will fall out of balance because once you remove the top predator, the plant-eaters will grow in numbers, they will eat all of the vegetation, and will either need to adapt or die. Predators are very important, as is everything in the food chain
The only effective methods to prevent oxygen toxicity are to limit the pO2, the time of exposure, and to give air breaks during oxygen breathing