Final answer:
Deoxyribonucleic acid (DNA) is the genetic material common to all living things. It is a double-stranded molecule composed of nucleotides that code for the development of life. DNA's universal presence across all organisms reflects the common ancestry and biochemistry of life.
Step-by-step explanation:
The genetic molecule common to all living things is deoxyribonucleic acid (DNA). DNA is an organic molecule that consists of two strands forming a double helix, with nitrogenous bases hydrogen bonded together. Each nucleotide of DNA consists of a nitrogenous base, a five-carbon sugar called deoxyribose, and a phosphate group. This genetic material is a polymer made up of four different molecules called nucleotides whose sequence codes for the development of all forms of life. Every organism on Earth shares this common genetic code, which provides compelling evidence that all life is descended from a common ancestor. This continuity in biochemical function as governed by DNA supports the Central Dogma of molecular biology, indicating the universality of the genetic code across all known life.
Genetic analysis enables the study of the relationships between species and contributes to our understanding of evolution. The genomic sequencing of thousands of species, including humans, helps to clarify the interconnectedness of life through the tree of life model and has significant applications in fields such as forensics and medicine. The biochemical unity of organisms, as stated by Jacques Monod, highlights the commonality of life's biochemistry, exemplified by the shared use of genetic material to give cells their characteristics.