Answer:
The Deoxyribonucleic Acid (DNA) is a molecule that contains the genetic instructions for the development, growth, and reproduction of all living things and many viruses. The DNA molecule is composed of two strands whose building blocks are named nucleotides. Each nucleotide consists of a sugar (deoxyribose), a phosphate group, and one of four bases: Guanine (G), and Thymine (T), Adenine (A) and Cytosine (C). These two strands wind around each other like a double helix by the pairing of complementary strands, where A always pairs with T, and C always pairs with G. The chromosomes are higher-order structures where the DNA molecule is packaged with histone proteins. In eukaryotic cells, the chromosomes are localized in the nucleus and mitochondria organelles, while in prokaryotic cells lack a nucleus and other organelles and thereby the genetic material is organized into a single chromosome found in an area of the cell cytoplasm named the nucleoid.