Duel is one against one, on the clock. You send someone a six-character code, you both get the same questions at the same time, and the faster correct answer takes the round. It runs in a browser, so the person you challenge does not need the app installed to play you.
A free wildlife app: 4,400+ species with real recorded sounds, 11 nature games and a free Daily 5, 1v1 quiz duels, conservation wins, and a safe Kids mode.
The Daily 5 is free. The full game library is part of Feravox Premium.