What does a syntax tree represent?

A syntax tree, also known as a parse tree, is a hierarchical representation that illustrates the grammatical structure of source code. It breaks down the code into its constituent parts, showing how different elements of the code relate to one another according to the rules of a programming language. Each node in the tree represents a construct occurring in the source code, such as operators, keywords, function calls, and other language-specific components.

This representation is crucial for various stages of the compilation and interpretation process. It enables the compiler or interpreter to analyze the structure and semantics of the code effectively, helping to ensure that it adheres to the language's syntax rules. The graphical nature of a syntax tree allows developers and tools to visualize how statements and expressions are connected, thus facilitating debugging and optimization.

The other options do not accurately describe what a syntax tree represents. A visual representation of server architecture pertains to systems design rather than code structure, the execution flow of a program relates to how code runs over time rather than its syntax, and a model of user interaction focuses on the interface and experience of users interacting with software, which is unrelated to the internal structure of code logic.