List Box Depending On Combobox And Add Or Delete Items To Range

i had a user form with a Combo box,list box,text box and a command button. I need the code that works upon selecting:

1)An Item from the combo box should display the list in the list box.

eg: If Country is selected from the combobox then the list box should contain all the names of the countries from the country Column

2)An item should be added to the list in the worksheet when an item is entered in the textbox.

Like wise, when an item is selected from the combobox from "Delete Items List" all the items relating to the item selected from the combobox should be displayed in the list box and a choice to delete the items relating to the combobox item should be provided.