You Don’t Need to Install a Task Manager: How to Manage Running Apps on Android
 

Google Play is full of task managers for Android. These utilities can show you apps running in the background, kill running apps, and otherwise manage your apps — but you don’t need to install any third-party software to do this.

We’ll show you how to quickly and easily kill and manage your running apps using only the software included with your Android phone. Third-party task managers are unnecessary and many include harmful features, like task killers.

http://www.howtogeek.com/166140/you-...ps-on-android/