due to the lack of Internet access(The study also shows that 3-400 000 teachers are not equipped for delivering online classes due to the lack of Internet access.'More)
in App Purchase(In-app purchase allows customers to purchase upgrades, new content, and complementary features directly within your app – without having to go back to the App Store or the Android Market. By simplifying and shortening the path to purchase, you’re more likely to keep your customer interested – and make a sale. In-app billing is the quickest and easiest way to monetize your app.)
