See the entire definition of Backbone. Biopsy: The removal of a sample of tissue for examination under a microscope to check for ... Blood clots: Blood that has been converted from a liquid to a solid state. Also called a t... Bone scan: A nuclear medicine technique for creating images of bones on a computer screen ...
Schmidt's study also stopped following the toddlers at age 3; she acknowledges that some cognitive changes may not occur until children are a few years older. TV exposure in babies younger than 2 doesn't do any good, Schmidt and Christakis agree.
According to the 1970 U.S. Census, the number of children under 5 years of age per 1,000 women aged 20 to 44 years, rose from 400 in 1940 to 551 in 1950; ten years later the figure was 667, the highest since 1890. And the baby boom created all sorts of incentives to buy a TV receiver.