= Organized contents =Air environment article: 2001-2022Water Quality Engineer: 2003-2022Water Quality and Environment Industry Article: 2018-2020Environmental Technician: 2001-2016= Problem notes, incorrect answer notes, test mode, and study mode are supported.[Essential access rights]- Save: Stores information on problems solved by the user within the app, and stores comprehensive problem-solving information such as personal information related to the problem, such as ‘favorites, incorrect answer notes’ and scores.- WIFI connection information: Detects Internet connection status and uses it to send advertisements.- In-app payment: Used to remove ads or use other services if necessary while using the app.