What is a key characteristic of JSON syntax?

A key characteristic of JSON syntax is that it uses key/value pairs enclosed in braces. This structure allows for data to be represented in an easily readable format that can be efficiently parsed and generated by machines. In JSON, data is organized into objects, which are defined using curly braces. Each key is a string followed by a colon and then the corresponding value, allowing you to represent complex data structures in a straightforward way.

This structure is beneficial for various applications, especially in web services and APIs, where JSON is often used to serialize data that can be transmitted over networks. The ability to nest objects and arrays within JSON also allows for a high level of complexity while still maintaining clarity and simplicity in syntax.

The other aspects mentioned in the options do not align with the core principles of JSON. For instance, indentation is not a requirement in JSON; it's commonly used for human readability, but the actual JSON format does not depend on it. Furthermore, there are no comments in JSON syntax, as it was designed to be lightweight and minimal. Lastly, JSON does not use sequentially numbered elements like some other data formats such as arrays in programming languages; instead, it relies on the key/value structure to index data.