1. Handling Concurrency in Node.js Node.js operates in a single-threaded event loop, which means it processes requests asynchronously, one at a time. However, for I/O-bound tasks (such as database queries, file reads/writes, network requests), you can take advantage of Node's asynchronous behavior.

Techniques for Handling Concurrency in Node.js:
Callbacks: Older but still commonly used. Callbacks allow you to run code after an asynchronous operation finishes.
Promises: A more modern and cleaner way to handle asynchronous code, especially with multiple concurrent tasks.
Async/Await: Syntactic sugar built on top of Promises. It makes working with asynchronous code easier and more readable.
Worker Threads (for CPU-intensive tasks): For CPU-bound tasks, you can use worker threads to offload work to separate threads.