Yes, you can close multiple apps which you have used recently. You get to see this in iOS as well as you will see it in Android phones as well. If you use an Android phone then you must have seen there that when you close the recent apps then you have to clear all here. Yes, you cannot clear all options on iPhone, but to close all applications together, we have to swipe up and use multiple fingers for this. So there you get to close all the applications at once.