Do we have a dedicated key (green color) for making or receiving calls?

There’s no dedicated physical phone key, as can be seen in the photos above, and you have to tap and slide the button on the screen to answer or reject incoming calls, which seems to be the norm in recent Android phones.
　

The display on this phone is blurred and far from satisfactory indeed, but that doesn’t necessarily mean it’s not responsive. So far as the simple actions like answering calls, switching apps, I didn’t get frustrated by touchscreen response.