Which of the following statements are true?
a. html is a programming language for web pages
b. html and css are both programming languages for web pages
c. there is no difference between html and html5
d. css can be included in an html document

d. CSS can be included in an HTML document

Explanation:

HTML (Hypertext Markup Language) and CSS (Cascading Style Sheets) are not programming languages. They are, in fact, a different kind of computer languages and are some of the essential tools used in common web pages nowadays.

HTML and HTML5 are different. The latter is a new version of HTML which implies some improvements such as the availability of other technologies and features not found in HTML.

HTML is a markup language, i. e., a kind of computer language like TeX, LaTeX, troff, among others, that defines the structure of a text, and it tells to a computer how to show it in a web page using tags embedded into the content of the document. For example, a paragraph is defined using a tag like this <p> text inside </p>, a title: <title> text inside </title>, and so on with images, tables, et cetera.

CSS is a style sheet language, that is, another kind of computer language whose main emphasis is the appearance of the web page, telling the computer the presentation the structured document is about to have, that is, how the document should look.

As a result, CSS is used to describe the presentation of documents written in HTML and can be included in it.

On the other side, programming languages are formal languages (like the ones of mathematics and logic), that is, with some rules and a particular syntax intended to "communicate instructions to a machine, particularly a computer" [Wikipedia, 2019], and some examples of high-level programming languages are those like C, Python, Fortran, Lisp, CommonLisp, Pascal, JavaScript, among many others.

a. HTML is a programming language for web pages

Explanation:

For web