Which of the following correctly identifies the building blocks of DNA?

The building blocks of DNA are nucleotides. Each nucleotide consists of three components: a phosphate group, a sugar molecule (specifically deoxyribose in the case of DNA), and a nitrogenous base (which can be adenine, thymine, cytosine, or guanine). These nucleotides link together in a chain through covalent bonds between the phosphate group of one nucleotide and the sugar of the next, forming the DNA backbone.

Nucleotides play a crucial role in the structure of DNA, as they sequence and encode genetic information. This sequence ultimately governs all biological activity in an organism. Understanding that nucleotides are the fundamental units of DNA helps clarify how genetic information is stored, accessed, and transmitted.

Other options represent different types of biological molecules: proteins are made from amino acids and are essential for cellular structure and function, amino acids serve as the building blocks of proteins, and carbohydrates are sugars that provide energy and structural support to cells. These options do not pertain to the structure of DNA.