How does IIS server handle requests concurrently?

I'm from C background, for a concurrent server written by C, when there is a new incoming request, the server program either spawns a new child process or a new thread to service the client. So if there are 10 users requests the index.html page at the same time, it could be 10 child processes generated on the server side, or 10 worker thread are used if the server is based on pre-threading worker thread pool.

But for web application(let's talk about not core who doesn't use Appdomain), below is my question:

Q1-IIS that hosts application will create a new Appdomain for the web application, but will a new Appdomain created to handle a new request? so if there are 10 requests then there will be 10 Appdomains being created? If not, how does IIS handle concurrent requests from multiple users?

Q2- What's the relationship between Appdomain and the worker thread in the CLR thread pool? does a new worker thread is used to run the application in the new Appdomain?