How to create a list of features in tree structure

I need to create a list of features as shown below

Animals
lion
Tiger
Dog
Cat
Vegetables
Brinjal
Potato
Carrot

It should have tree structure like within animals i should have details like lion, tiger, dog etc.
Someone please tell me how to do it using xml. I am new to xml.

Any good tutorials for creating list in tree structure?

Urgent help required

Something like this?

Code:

---

<?xml version="1.0" encoding="utf-8"?>
<items>
  <itemlist type="Animals">
    <item>Lion</item>
    <item>Tiger</item>
  </itemlist>
  <itemlist type="Vegetables">
    <item>Potato</item>
    <item>Carrot</item>
  </itemlist>
</items>

---

@JapyDooge: Thanks for the help.

I have written xml code for features to be placed in tree structure. Can I see the output of xml code in GUI format? I need to add collapse and expand feature to the list so that if I press a button the list should expand, and if I press it once again the list should compress. If yes what is the procedure to do it? Any tutorial to do it?

Urgent help required

Thanks in advance