Android AND-802 - Android Security Essentials

What is the message "File Written to external memory" which appeared when the app user clicks "Save" button in the following image?

Android uses “Intents” to communicate and send data between different components which make it vulnerable to malicious attacks. Which of the following choices are component-level Permissions to protect this type of communication? (Select Four)

If your database contains sensitive information, it is recommended not to store it on external storage. If you want to share the database with other applications, then you have to use a ……………………………………………. to protect your app’s data.