A question aboout Render a Class Component to the DOM

nope, that’s not right.

{/*<One />
<Two />*/}

Yes it is. Are you sure you did it right?

yes
https://stackblitz.com/edit/react-i1vumx?file=components%2FTypesOfFood.js

What is the problem? It is working like it should.

Considering you have deleted the component file with the One/Two components, you might as well just delete them from the JSX.