Sandra Tennyson is Ben's mom,Gwen and Ken's aunt, Kenneth Tennyson's grandmother, Carl Tennyson's wife, Frank and Lily Tennyson's sister in-law and Max and Verdona Tennyson's daughter in-law. Sandra Tennyson is called Mother in the credits of Ben 10 Returns Part 1 and Ben 10 Returns Part 2.
Sandra Tennyson has only made one appearance in the Ben 10 Series.
Sandra Tennyson has only made one appearance in Ben 10 Alien Force.

Sandra Tennyson's First Appearance
Goodbye And Good Riddance

Sandra Tennyson's Last Appearance
Ben 10 Returns Part 1