Single-Threaded Execution: JavaScript operates on a single thread, meaning it executes one task at a time using the call stack, where functions are processed sequentially.

Call Stack: Picture the call stack as a stack of plates. Each time a function is invoked, a new plate (function) is added to the stack. Once a function completes, the plate is removed.

Web APIs: Asynchronous tasks like setTimeout, DOM events, and HTTP requests are managed by the browser’s Web APIs, operating outside the call stack.

Callback Queue: After an asynchronous task finishes, its callback is placed in the callback queue, which waits for the call stack to clear before moving forward.

Event Loop: The event loop constantly monitors the call stack. When it's empty, the loop pushes the next callback from the queue onto the stack.

Microtasks Queue: Tasks like promises are placed in a microtasks queue, which has higher priority than the callback queue. The event loop checks the microtasks queue first to ensure critical tasks are handled immediately.

Priority Handling: To sum up, the event loop prioritizes microtasks before handling other callbacks, ensuring efficient execution.