the Answer...

OK, at its most basic, here's what was on the previous page:

A bunch of letters
A sketch of the globe
A solid line

Some other answers might be: a bunch of words, or a few sentences, or a heading and some paragraphs. Those are certainly true also. Those are all things built from a bunch of letters. OK, there are many ways to answer that question. So what is the "official" answer?

Here's the official answer, which mostly comes from the definition of HTML itself. The things that made up that page were:

A bunch of characters.
A horizontal rule (fancy name for a line).
The characters and an image are grouped into paragraphs.
The paragraphs & rule make up the page.

Objects

Those items singled out above have a special distinction: they are Objects. Web pages are made of objects. That word has a certain meaning in computer science, but it suffices to think of its generic meaning, "thing". Some things have a special distinction of being objects, as far as a web page is concerned, while other things don't. Characters and paragraphs are objects. Words, sentences, and headings are not objects, at least not for a web browser.

Notice that some objects are built up from other objects. Each character is an object on its own, and a bunch of them together make up a paragraph object. One or more paragraphs, in turn, combine to make a page object, the web page itself.

Properties

Objects have Properties. The rule (line) object immediately below this sentence, for example:

Its properties are that it is centered on the page, it's 3 pixels tall, and its width is 60% of the width of the browsers window (no matter how wide that may be - try resizing the window and watch the line change).

The characters atop this page, "the Answers...", indeed make a heading, but a heading is not an object. A heading is a property of a paragraph.

So, to understand how to create and modify web pages, all that's needed is to know what the web page objects are, and what those objects' properties are.