Can you identify the gas that makes up most of Earth's atmosphere? If yes, you may be surprised to be among the minority in the United States. (Hint: It's not oxygen.) But if you know which kind of radiation that sunscreen protects against, you're in good company.

The American public's knowledge of basic science and technology varies widely, according to the results of a 13-question survey by the Pew Research Center and Smithsonian magazine.

About 78 percent of the public know red blood cells carry oxygen to the body, whereas 83 percent know sunscreen protects the skin from harmful ultraviolet rays, the poll found. Most know the Earth isn't such a static place, with 77 percent choosing "True" over "False" when told that the continents have been moving for millions of years and will keep moving in the future. [Americans' Science & Technology Smarts (Infographic)]

Another 77 percent correctly answered that antibiotic-resistant bacteria is the main reason scientists are concerned about the overuse of antibiotics. That might be because superbugs like methicillin-resistant Staphylococcus aureus, better known as MRSA, get a lot of attention in the news. But even though the controversial drilling technique known as fracking has been emerging as a hot-button environmental and political issue, only 51 percent of the public know that natural gas (not coal, diamonds or silicone) is extracted in the process, the poll found.