Using > vs without >


What is the different between using > and without >?
any reason using >?


in css? > will only affect the direct children, look at this html code:

  <p>i am affected</p>
    <p>i am not</p>

if i now do: body > p {color: red;} only the first paragraph gets affected (since it is a direct of body, where the paragraph inside the doesn't), if i just where to use body p, all paragraph somewhere in body (which are all paragraphs) would be affected