Block scope in JavaScript is introduced using the let keyword, which allows variables to be declared with block-level scope, while const is used to declare constants. The var keyword does not provide block scope and was used in older versions of JavaScript.

If you forget to include a "break" statement in a switch case, it will lead to a bug where the function may not behave as expected. Instead of stopping after the first matching case, the switch statement will "fall through" to subsequent cases, causing unintended behavior. The correct option is to use a "break" statement to exit the switch block after handling a case. JavaScript doesn't automatically insert "break" statements, and it doesn't throw an error for missing "break" statements.

Closures allow a function to access all the variables and other functions that are in its scope when the function was created. This feature enables powerful patterns in JavaScript, like data encapsulation and private variables. Understanding closures is essential for advanced JavaScript development.

Arrow functions have no impact on the call stack, as they do not create their own execution context or call themselves recursively. This means they don't contribute to the call stack depth, making it easier to avoid stack overflow errors in certain cases. However, it's essential to understand how this behavior can affect debugging and performance when using arrow functions in JavaScript.

The Fetch API is commonly used for making asynchronous network requests, including fetching data from APIs and updating web pages without refreshing. While WebSockets are used for real-time communication, REST and GraphQL are architectural approaches, not technologies.

Closures provide a form of data isolation, which is essential for data privacy in JavaScript. They allow you to encapsulate data within a function's scope, making it inaccessible from the outside, thus achieving data isolation and privacy. This concept is often used in creating factory functions.

By default, an AJAX (Asynchronous JavaScript and XML) call does not trigger a page reload. AJAX requests allow you to retrieve or send data to the server without reloading the entire web page. This behavior is essential for creating interactive web applications that update content dynamically without disrupting the user experience.

The HTTP status code 204 No Content indicates that the server has successfully processed the request, but there is no data to send back in the response body. It is often used when a request doesn't return any content, like in a successful DELETE request or when fetching data that hasn't changed since the last request.

In the context of making HTTP requests, the object that represents the response to a request is simply called the "response" object. This object contains information about the response, including the HTTP status code, headers, and the response body. Developers can access and manipulate this object when working with web APIs or performing HTTP requests in JavaScript.

The querySelectorAll method can select multiple elements that match a specified CSS selector. It returns a NodeList containing all matching elements. The other options select only single elements.

Using a switch statement with a very large number of cases might affect the performance of your JavaScript code. The larger the number of cases, the longer it may take to find a matching case, impacting the execution speed of your code. It's important to consider this when using switch statements in performance-critical code.

You can define a property inside a JavaScript object using dot notation, where you specify the object name followed by a dot and then the property name. For example: objectName.propertyName. This is the most common way to define object properties.