replace new line with paragraf on answer

I do not know why the new line in the answer form are not replaced with <p> tags like they do on the question form.

For example in question form when I press Enter to go on the new line automatically the text is wrapped in a <p> tag, but this is not happening in the answer form, it just puts the content on a new line when I am looking at the page source (no <p>:wink:.

How can I solve this problem?