Answer:
DNA molecules are composed of four nucleotides, and these nucleotides are linked together much like the words in a sentence. Together, all of the DNA "sentences" within a cell contain the instructions for building the proteins and other molecules that the cell needs to carry out its daily work.
Step-by-step explanation:
A strand of DNA is much like an extremely long sentence that uses only four letters. DNA actually has two strands, much like a zipper and the nucleotides are like the teeth of that zipper. This two-strand system is the key to how DNA is able to make copies of itself.