The Android OS is a mobile operating system developed by Google, based on a modified version of the Linux kernel and other open source software and designed primarily for touchscreen mobile devices such as smartphones and tablets.

• The statement above should be written in a quoted box since you've taken an exact word-by-word definition from Wikipedia. It's good that you link the definition to the original source but it would be neater if it is put in a quote box.

• Even if you have quoted every single source by embedding the article's link to a few sentences, you still need to list up our references at the end of your article.

• You have some issues with your images, apart from what is yours, the second image can't be used because it is copyrighted while the third image was not properly credited.

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• The statement above was taken from the source of your 2nd image. Unless you have obtained written permission, you weren't allowed to use the picture.