Answer 1

The tag should be <br> as it has no end tag. It is used anywhere in html where you would like a line break (basically the same as pressing 'Enter' on your keyboard once).

Answer 2

The <td> elements are the data containers of the table.
They can contain all sorts of HTML elements; text, images, lists, other tables, etc.
simple example:
https://code.sololearn.com/WsocEw0a3R1F/?ref=app