"When a user clicks on a button, all \<p> elements will be hidden:" - here the "\<p>" is taken as html tag due to which text is moving to next line. The intention of author is to say that all paragraph (\<p>) tags will be hidden. The "\<p>" itself is not showing as it's considered an HTML tag. I have added an escape character in front.
* fixed typo in first line
There was becuase instead of because!
* Removed second typo.
I've removed the second type as requested, thank you I've totally not seen this at first!