Cervical cancer is caused by severe abnormal changes in the cells of the cervix. Most precancerous or cancerous cell changes occur in the cervix at the transformation zone, because these cells normally undergo constant change.
In baseball, a balk is called by an umpire. Balk rules protect runners from being deceived by the pitcher. If the ball is thrown before the batter gets settled in the batter's box, the umpire will call a balk. If a pitcher begins his delivery motion but then stops, he'll be called for a balk.
A bat is a stick used by the batter to hit the baseball. Baseball bats were traditionally made from ash, though other hardwoods have been used. Hollow metal (such as aluminum) and composite bats are now standard in most amateur baseball and some professional leagues outside of North America.