The DNA double helix is held together by hydrogen bonds and the nucleotide bases Adenine, Guanine, Cytosine, or Thymine. Check out the source I provided. There's a great diagram of the double helix.Source(s): http://www.ba-education.demon.co.uk/for/...eport Abuse. Hydrogen bonds hold the two helices together to form a double helix. I also remember somethign called base stacking, which if i recall was hydrogen bonding of the same strand, which promoted the helical nature and enforced rigidity of the structure.
Norfolk, Nebraska. Norfolk (/ËnÉÉrfÉÉrk/ or /ËnÉÉrfoÊk/) is a city in Madison County, Nebraska, United States, 113 miles northwest of Omaha and 83 miles west of Sioux City at the intersection of U.S. Routes 81 and 275. The population was 24,210 at the 2010 census,[5] making it the ninth-largest city in Nebraska.
Virginia has 11 Metropolitan Statistical Areas; Northern Virginia, Hampton Roads, and Richmond-Petersburg are the three most populous. Richmond is the capital of Virginia, and its metropolitan area has a population of over 1.2 million. As of 2010, Virginia Beach is the most populous city in the Commonwealth, with Norfolk and Chesapeake second and third, respectively. Norfolk forms the urban core of the Hampton Roads metropolitan area, which has a population over 1.6 million people and is the site of the world's largest naval base, Naval Station Norfolk.