"Americans are knowledgeable about basic scientific facts that affect their health and their daily lives. But the public is less able to answer questions about more complex science topics," the report notes.
I'm not going to tell you the results - they break it down by demographic and by question - because the percentages of how many people answered the questions correctly will give away the answers. But you can read about them yourself after the quiz.
What I will tell you is that I answered all 12 correctly, and only 10% of Americans overall were able to do that. The quiz is part of a larger study of attitudes about science in the U.S. - you can read all about that in the report (linked above).
I found out about the quiz because I lurk on a NASW mailing list and the various contributors were lamenting the sad state of scientific knowledge in the general public, and how much of the blame the media should bear for that. Hopefully, sites like Scientific Blogging will change that trend.