In order to avoid getting lost when hiking in the mountains, you have taken with you a mobile device with an app that has all the maps of the local trails. When you look at the map, you see that the blue dot indicating your location hasn't moved since you left your house. Which setting on your mobile device must be enabled for the app to function properly?

In order to determine your approximate location, location services on your device may use the Global Positioning System (GPS), which depends on satellites, Bluetooth, Wi-Fi, or cellular location services. You can enable, disable, or conditionally enable location services for certain apps on your phone that are dependent on the service in order to work properly. In airplane mode, all network connectivity is disabled.