I am a newbie to linux(Red Hat 8.0), and was just invesigating sudo etc. i changed the /etc/sudoers code by
simply taking out the comment sign of the line # %wheel All=(All) All
and so it was %wheel All=(All) All
I then added an (imaginary) user to this group, and checked if i could carry out root commands "useradd" and so on. The problem is even when i changed the code back and removed the user from the wheel group, all of my (imaginary) users are able to execute root commands.
Could anyone please help me fix it.
Also i'm looking to give imaginary users the ability to change groups, what would i put in sudoers, maybe something like this:

user1 ALL = /usr/bin/gpasswd

Thanks in advance
Rob