Complex sentence: Antiparellel strands in DNA double helices are non-covalently bound by hydrogen bonding between Watson and Crick base pairs; nitrogen and oxygen therefore maintain the potential to weaken the integrity of DNA when exposed to air.
Split into simpler sentences: Antiparellel strands in DNA double helices are non-covalently bound by hydrogen bonding between Watson and Crick base pairs. Nitrogen and Oxygen therefore maintain the potential to weaken the integrity of DNA when exposed to air.