The structure of dna molecule can help account for the great variety of life that exist on earth because of its double helix shape it can easily recombine and split to form a replication of itself also because of its shape nucleotides are freely and easily pared up to the bases of each lather have (thymine-adenine and guanine-cytosine) which when this happened succesful replication of dna can take place and also cell division.

Its not the structure that is responsible for the variety of life, it is the arrangement of the bases that is responsible for this variation of life