[&] Which structure does XML use to organize data?
- Array format
- Circular graph
- Linear structure
- Tree structure -- Correct

[&] What is XML primarily used for?
- Simplifying hardware configurations
- Displaying visual elements on web pages
- Supporting modern programming languages
- Structuring, storing and transporting data -- Correct

[&] What does 'well-formed' XML mean?
- XML with correct syntax and a root element -- Correct
- XML using more than one data type
- XML document with no technical errors
- XML file size below a certain limit

[&] What role does a DTD play in XML?
- It specifies the structure of an XML document -- Correct
- It sets the format for XML error messages
- It converts XML data to JSON format
- It defines styles for XML elements

[&] Why is it important that XML tags are case-sensitive?
- To avoid confusion between similar tags -- Correct
- To ensure tags are unique
- To match with predefined HTML tags
- To strictly follow JSON format

[&] How does XML differ from HTML?
- XML tags are not predefined -- Correct
- XML does not use tags at all
- XML is used primarily for data display
- XML tags are predefined like HTML