XML and XSL Technologies

XML stands for Extensible Markup Language, a text-based markup language designed to store and transport data in a structured, hierarchical format that is both human-readable and machine-readable.

XML enforces well-formedness rules where elements must nest properly without overlapping - an end tag must match the most recent start tag. Attributes must be quoted and have unique names within an element.

XML declaration is a processing instruction that starts with , making option C the correct syntax. This optional declaration specifies XML version and encoding at the document start.

XML allows two equivalent syntaxes for empty elements: a full open/close tag pair with no content, or a self-closing shorthand. Both are valid and interchangeable.

XML comments are delimited by , allowing documentation within XML documents that parsers ignore. Option A shows the correct syntax though the example appears to have a minor formatting issue.

XML (eXtensible Markup Language) is a recommendation specified by the World Wide Web Consortium (W3C), the main international standards organization for the World Wide Web. The W3C XML specification was first published in 1998 and has gone through multiple versions (1.0, 1.1). W3C is responsible for maintaining and standardizing web technologies including HTML, CSS, and XML to ensure interoperability across different platforms and systems.

XML Schema is designed to be self-descriptive, providing a way to define the structure, content, and data types of XML documents. Unlike DTDs, XML Schema is itself written in XML and allows for complex type definitions and constraints.

XML Schema is the standard W3C recommendation for describing and validating XML document structure. It defines elements, attributes, and data types, replacing the older DTD approach with more powerful validation capabilities.

XML serves as the foundation for many markup languages. WML (Wireless Markup Language) and WAP (Wireless Application Protocol) are XML-based technologies designed for mobile and wireless devices, making XML their 'mother' or parent technology.

XML is both free (open standard) and extensible (you can define your own tags and attributes). The 'X' in XML stands for Extensible, which is its key feature allowing custom markup languages for specific domains.

XML element names cannot contain spaces. Option B '' contains a space which violates XML naming rules. Element names must start with a letter or underscore and can contain letters, digits, hyphens, underscores, and periods only.

XSL stands for EXtensible Stylesheet Language. It's a family of languages used to transform and render XML documents. The spelling is EXtensible (with 'e'), not EXtendable (with 'd').

XSL has three components: XSLT (for transformation), XPath (for navigation), and XSL-FO (for formatting). XSLT transforms XML to other formats, XPath navigates XML documents, and XSL-FO handles formatting for presentation.

XSL processors parse the XML source tree and match nodes against template rules in the stylesheet. Each template defines how to process a particular node or set of nodes, enabling recursive transformation of the entire document.