DNA (deoxyribonucleic acid) is the hereditary material in almost all living organisms, carrying genetic instructions for development, function, growth, and reproduction. It consists of sequences of nucleotides that encode genes, which determine traits such as eye color, height, and susceptibility to certain diseases. DNA is passed from parents to offspring during reproduction, with variations introduced through genetic recombination and mutations. Understanding DNA has enabled advancements in genetic research, forensic science, and personalized medicine.