How are you supposed to maintain track of the items that contain data in an array that is only half filled?

In what situations is it helpful to have data stored in an array with several dimensions?

Which is not true?   Group of answer choices An array is a group of variables that all have the same name. An array is a group of variables that all have the same data type. The variables in an array do not have to be stored in consecutive memory locations in the computer's internal memory. All are true.