stars and stripes 2 italics the national anthem of the united states of america based on a poem written by francis scott key on september 14 1814 and set by him to the melody of the english song to anacreon in heaven officially adopted by the u s congress in 1931 examples from the web for star spangled banner expand
The two strands of DNA are held together by weak hydrogen bonds (remember, something must hold them together!) between the nitrogenous bases. The interesting (and very important) aspect of the Watson-Crick model is that these hydrogen bonds are base specific.
The regular pairing of bases in the double-helical DNA structure suggested to Watson and Crick a mechanism of DNA synthesis. Their proposal that new strands of DNA are synthesized by copying of parental strands of DNA has proved to be correct. The DNA strand that is copied to form a new strand is called a template. The information in the template is preserved: although the first copy has a complementary sequence, not an identical one, a copy of the copy produces the original (template) sequence again.