Perhaps you've heard that everything you eat is made of corn. While that's not precisely true, it's not far off the mark, either: CNN a few years ago quoted a University of California-Berkeley biologist who likened Americans to "walking corn chips." (The same scientist tested a strand of Sanjay Gupta's hair, and determined 69 percent of the correspondent's carbon came from corn.)

In the form of high-fructose syrup and other derivatives, corn shows up in frosting, hush puppies, wallpaper, shaving cream, fireworks, instant pudding, shoe polish, chalk and marshmallows - and those are just a few of the 4,200 uses listed by the Kentucky Corn Growers Association.

But there's a world of difference between industrially processed corn and the fresh ears just now starting to appear at the market. Here, seven things to know about corn that's not destined to become insecticide:

1. Until very recently, archaeologists had trouble explaining the origins of corn, or maize, since the plant doesn't grow wild anywhere on earth. Then in the 1930s, a Cornell University graduate student proposed teosinte, a hard-cased Mexican grass, as corn's likely ancestor. Later genetic research proved George W. Beadle right, showing maize was 9,000 years ago domesticated from teosinte by farmers living in a southern Mexican river valley.

2. Although corn got its start in central America, it's now grown on every continent but Antarctica. Forty percent of the global harvest comes from the U.S.

3. When eating corn, you have hundreds of chances to get a kernel stuck between your teeth: The average ear has about 800 kernels.

4. While corn is rarely classified as a health food, corn is a good source of fiber and manganese. It's also a gateway grain for children who otherwise shy away from whole grains: A 2009 study showed young people with Type 1 diabetes prefer whole grain cornbread over every other whole grain food.

5. Corn typically grows to a height of about 8 feet, supported by a root system that extends more than six feet underground. But to ensure corn "high as an elephant's eye" for the 1954 filming of "Oklahoma!," crews planted 2,100 stalks in southern Arizona one year before shooting. (Oklahoma had too many oil wells to pass as a turn-of-the-century version of itself.) The corn topped out at 16 feet, leading lyricist Oscar Hammerstein to say it was as high "as the eye of an elephant who is standing on another elephant."

6. Corn's synonymous with summer, but high heat can encourage microbal contamination. At a supermarket, opt for corn stored in a refrigerated area. And when shopping at an outdoor market, look for corn that's being kept out of direct sunlight.

7. It's best to eat corn right away, but if you plan to refrigerate it for a few days, leave the corn in its husk and seal it in a plastic bag. To freeze corn, blanch the husked ears in boiling water for about five minutes. Cool the corn in ice water; remove the kernels from the cob (or not, if you'd prefer to enjoy corn-on-the-cob this winter); seal in a plastic bag; freeze.