The steps of the dna ladder are made of

The steps of the DNA ladder are made of two nitrogenous bases that are held together by either two or three weak hydrogen bonds.

DNA (deoxyribonucleic acid) is a hereditary material that carries genetic instructions used in building and maintaining all living organisms and many viruses. DNA is formed by base pairs joined to a sugar-phosphate backbone. The rungs of the DNA ladder contains four nitrogenous bases; adenine, thymine, cytosine and guanine. Each rung of the ladder is made up of two nitrogenous bases that are held together by weak hydrogen bonds.

relative humidity, temperature and dew point -- are bound together in the mathematical relationship below. relative humidity changes when temperatures change. because warm air can hold more water vapor than cool air, relative humidity falls when the temperature rises if no moisture is added to the air. so i would say a

amber has allowed scientists to study dna that has been preserved over millions of years.