Can anyone tell me how to do the following: 
I have a drop down list on a field on a form. Depending on what is selected on this list will determine the option on the next drop down field.
E.G
List 1
Dog
Cat
Fish
Following lists appear depending on which in List 1 is selected:
List 1a or List 1b or List 1c
Fido Molly Fred
Laddy Misty Wanda
Sam Tom Nemo

I have a drop down list on a field on a form. Depending on what is selected on this list will determine the option on the next drop down field.
E.G
List 1
Dog
Cat
Fish
Following lists appear depending on which in List 1 is selected:
List 1a or List 1b or List 1c
Fido Molly Fred
Laddy Misty Wanda
Sam Tom Nemo