What are the building blocks of dna? what are the three parts?

A nucleotide is DNA's building blocks. A nucleotide is made up sugar, nitrogenous base and one phosphate. The nitrogenous base can be adenine, cytosine, guanine or thymine. They are often shown on DNA models as A,C,G,T. The three parts are phosphate, sugar and nitrogen base.
  

Ithink its because more have died recently than in the past.