Answer: Oxygen is the most likely to be correct (could be carbon dioxide if using a certain time limit but highly doubt it).
Explanation: I say this Bc unless that frog was being tortured inside it’s tank, I doubt it would be carbon dioxide or nitrogen... simply put, carbon dioxide is the air we breathe out, and the tank would have to be completely sealed in order to collect it later on (and the frog wouldn’t survive very long like that either) Nitrogen is just a bad idea ngl, it’s basically the atmosphere we live in but it can be used as a coolant which I doubt the frog would even need so yeah. Hope this helps
