How do I restore individual text line animation in Keynote?

In my Keynote presentation, I like to have lists in the text box. Then I use animation to introduce each line separately when I want it to appear. But lately, that option seems to have disappeared. Now the only option available in my animation tab is the entire text in the box, as if it is an image or a solid unit instead of separate text lines.

How can I regain the individuality option?

Thank you

[Re-Titled by Moderator]