Roundworms have taken this last body plan and adapted to thousands of environments with it. From microscopic to maybe a meter long, roundworms are just what they sound like-round worms. At one end, they have a mouth, at the other, an anus, with a tube digestive system in between.
Availability of two-factor authentication for Apple ID Two-factor authentication is an extra layer of security for your Apple ID designed to ensure that you're the only person who can access your account, even if someone knows your password.
Two-Factor authentication is designed to add a second form of authentication to the login process, usually in form of a code that is send to the user. PayPal for instance is offering VeriSign ID Protection devices that act as a second layer of authentication.