Go to Gmail settings in the Gmail app (using the gear icon in the app) and then tap the "Google Apps" button that appears there at the bottom. That should let you select which Google apps you want to be used by Gmail and which ones you don't want to.
I tried clicking on the gear at the bottom that manages accounts, but wasn't clicking that pancake stack/coin stack icon at the top which gives access to the other gear/settings.
I tried clicking on the gear at the bottom that manages accounts, but wasn't clicking that pancake stack/coin stack icon at the top which gives access to the other gear/settings.