One coiled spring is shown in the diagram.

a teacher modeled part of a dna molecule using two of these coiled springs.

which part of the dna molecule was the teacher most likely modeling?

protein
gene
nitrogen base
backbone

Spring can be considered as backbone of the DNA.(as picture is missing there)

Explanation:

In DNA double helical model two main structure are there-

1- Backbone consist of phosphate group and the pentose sugar. It is like two vertical columns of a ladder. In helical structure two complementary stands are there one is 3' to 5' and another one is 5' to 3'.

2- Nitrogenous bases are like horizontal bars of ladder attaching two vertical strands. There are 4 kinds of nitrogenous base ADENINE , THYMINE , GUANINE , and CYTOSINE. One more nitrogenous base URACIL is also there but found in RNA not in DNA.

DNA is made of nucleotide and a nucleotide molecule is made of pentose sugar(deoxyribose) ,phosphate group and nitrogenous base.

i think that it is c, d, and e, hope this