Answer:
You should have a line on which you can add information below the <style> tag and above </style> tag. simply add the body tag after <style> tag.
Explanation:
From the below code you can understand it how you can change the background color of a section in html.
<!DOCTYPE html>
<html>
<head>
<style>
body {
background-color: #afafaf;
}
h {
background-color: #00b33c;
}
p {
background-color: #00d33c;
}
</style>
</head>
<body>
<h1>Header with green background</h1>
<p>Paragraph with lite green background</p>
</body>
</html>