The main menu item (Bible Study) of my website www.GodlyWriter.com/study provides a drop down list. I created sub-menus (New Testament & Old Testament), these two sub-menus show-up on the main menu item. However, I also created additional sub-menus of the two sub-menu items New Testament and Old Testament. These additional menu items do not show up in the drop down list. How do I get these sub-menu items of NT and OT to show up in the list?

There is a setting on your menu module.
You need to set the module to show all levels of your menu.

PS. This is a Joomla! thing/module not a K2 one.

Sorry, I added K2 almost immediately after getting Joomla. I wasn't thinking about the Joomla menu module in relation to my K2 content as a Joomla thing. :oops: Thanks for replying anyway! I did set it in the menu module though and it would only show the first sub-menu and would not show a menu item below the first sub-menu. I guess I need to find the Joomla community on that one.

If you want to show all levels of your menu, simply select "All" in the End Level list.
This option is located in your menu module.