Descendant selectors vs. element selectors

Question

Directly using the element selector to define em has the same function as the descendant selector

Answer 1

Yes. However, sometimes, we will choose to use the descendant selector instead of the element selector. For example, let me write a piece of code for you. In the following code, I want to modify the font color of the first em:

<div><em>我是程序界的彭于晏</em></div>
<span><em>我是程序界的周杰伦</em></span>

If the element selector is used directly here, the color of the two sentences in em will be changed, but I only want to change the words in the first em, then at this time, the descendant selector will show its effect.