I have just jumped from windows to OS X so i am not an expert and my question might be silly. 1) how do i check what apps are running. for example when i open safari and after a while close it by pressing the X circle button on top left , i see the dock and i see a blue circle under the safari icon and i figured out that it still runs. i right click on it and then i press close and the blue circle dissapears. is safari(and not only safari) running ? how do i check the apps that are running or how do i close an app permanently ? 2) how could i enhance my macbook air's battery life? when browsing i think that the battery will not last for 5 hours as claimed . is there a way to do that from the system preferences?