Pure aluminium is only used when you need to have very little reactivity.

General construction steel has >98% weight iron. Around the same as most aluminium alloys.

No, the html file itself. It just contains elements like a paragraph, image, list, table,… just like a word document.

A word document can also contain a script, as can html pages. It’s why I thought these two were the closest match. Nobody is going to call those programming languages.

A PowerPoint, word document or even a text file or picture. There is only a description in the file of what it holds and it’s up to the program that reads it, how it will visualize or interpret it.

A word document or PDF would be the closest.