And ABC's would be AIRWAY,BREATHING, CIRCULATION.
Airway - make sure it is open, learn how to clear
Breathing - if their not, check the airway and begin rescue breathing
Circulation - make sure blood is going where it is supposed and not were it isn't. Don't forget to check for internal bleeding also (some additional training may be needed here).

You can also add "D" to that for "deadly poisoning".

That includes internal (something ingested or inhaled) & external (skin contact - poison ivy family, insect stings - particulary bees & wasps, and venomous reptiles - a whole 'nother thread).

Happy learning!