When a solution of cesium chloride (cscl) is subjected to high-speed centrifugation, a stable density gradient is formed. meselson and stahl found that when cell contents were subjected to centrifugation with a cscl solution, a band of dna formed at the cscl density that matched the density of the dna. this technique is called density-gradient centrifugation. the test tubes below show the results of density-gradient centrifugation of five different dna samples. assign letters a-e to the pictures above. dna from e. coli cells grown in ^5n dna from e. coli cells grown in ^14 n a 1: 1 mixture of dna from cells grown in 14^n and cells grown in ^15 n a 1: 1 mixture of dna from cells grown in 14^n and 15^n, heated (to disrupt hydrogen bonds) and cooled (to allow reannealing) dna containing one strand of ^15 n-dna and one strand of ^14 n-dna