First react code gets an error?!?

Question

Why I will take an error in this code?
https://code.sololearn.com/W8hbxpQM16va/?ref=app .

Answer 1

https://code.sololearn.com/WEWoOeeHIoPO/?ref=app

Answer 2

Hello, you must put the code "react" at the end of the body, that makes the elements of the "dom" load first, which is where the output of your code has to be shown, greetings
sorry for the double answer but here it is public