Callback promise async…

From yesterday we had to solve three big parts mainly about asynchronous.
Part 1 was mainly about understanding and the other two were the main.
Part2 had questions of Callback, PromiseConstructor, BasicChaining(promise), PromiseAll and AsyncAwait. The third one was difficult.
And for part3, it was about Fetch API. I had trouble understanding what to return.
However, finally figured it out after carefully reading the links that were given.
And every time I should remember to be careful with typos. Very annoying. (Had trouble with the capital letter today)

Callbacks can be any function that another function calls or
callbacks can be more explicitly an asynchronous callback as in one that will get pushed back on the callback queue in the future.

The Promise object represents the eventual completion (or failure) of an asynchronous operation and its resulting value. A promise creates a substitute for the awaited value of the asynchronous task and lets asynchronous methods return values like synchronous methods. Instead of immediately returning the final value, the asynchronous method returns a promise to supply the value at some future point.