Answer:
The solution is as follows:
<!DOCTYPE html>
<html>
<head>
<style>
h1, h2, h3, h4, h5, h6 {
color: red;
text-align: center;
}
</style>
</head>
<body>
<h1>HTML</h1>
<h2>Heading 2</h2>
<h3>Heading 3</h3>
<h4>Heading 4</h4>
<h5>Heading 5</h5>
<h6>computer science as least important heading</h6>
</body>
</html>
Explanation:
The most important heading in html is defined using h1 while the least is defined using h6.
As far as this question is concerned, h2 to h5 are not needed; however, I've included them as part of the solution.
The CSS Part of the solution
<em><style>
</em>
<u><em>h1, h2, h3, h4, h5, h6 {
</em></u>
<em> color: red; -> </em><em>This changes the color of all headings (h1 to h6) to red</em>
<em>text-align: center; -> </em><em>This centralizes all headings (h1 to h6)</em>
<u><em>}
</em></u>
<em></style>
</em>
<em>--------------------- End of CSS</em>
The html part of the solution
All headings from the most important (h1) to the least important (h6) are defined here
<em><h1>HTML</h1>
</em>
<em><h2>Heading 2</h2>
</em>
<em><h3>Heading 3</h3>
</em>
<em><h4>Heading 4</h4>
</em>
<em><h5>Heading 5</h5>
</em>
<em><h6>computer science as least important heading</h6>
</em>