1. A sugar molecule: This is a deoxyribose sugar, which is a five-carbon sugar.

2. A phosphate group: This is a negatively charged group containing phosphorus.

3. A nitrogenous base: There are four different nitrogenous bases found in DNA:

* Adenine (A)

* Guanine (G)

* Cytosine (C)

* Thymine (T)

The nitrogenous base is attached to the sugar, and the phosphate group is attached to the sugar's 5' carbon. These nucleotides link together to form a long chain, with the phosphate group of one nucleotide bonding to the sugar of the next. This forms the backbone of the DNA molecule.

The sequence of nitrogenous bases along the DNA chain determines the genetic information it carries. Adenine always pairs with thymine (A-T), and guanine always pairs with cytosine (G-C) through hydrogen bonds, forming the double helix structure of DNA.