The second chance can be found in every game mode, and it allows you to keep playing if your answer is not correct. There are two ways in which you'll be able to keep playing without losing your turn: you can use your gold bars or watch an ad.
If you decide to use gold bars, bear in mind that the cost will increase each time you use the second chance feature. The initial cost is 100 gold bars, which will increase by 100 every time. You'll be able to use this as many times as you want, as long as you have enough gold bars to exchange.
If you decide to watch the ad, you'll be able to play for free, but you'll only be able to use this option one time per turn. If you decide to use the second chance again, you'll have to use gold bars.