12 or 24 questions.
Each question has an answer of one of the elements.
ie: Horned frog belongs to...
Answer: Life
Every question should be multiple choice, with the answers being all of the 12 elements.
I could try and make the questions, so if anyone would be happy to make it for me (Because I can't yet), you will be in my debt*.
*Which will be payed by a reputation point.