Question

.... Are used define individual data items in an XML document.

Answer 1

Answer:

Element

Explanation:

Elements are used define individual data items in an XML document

Type of element must be defined also. Element type declarations declare the type and number of elements that may appear in an XML document, what elements may appear inside each other, and what order they must appear in

All element types are stated in the Document Type Definition (DTD) using an Element Type Declaration validity constraint.

An element type cannot be declared more than once