A genome is the complete set of genetic material in an organism, including all of its genes. It contains the instructions needed for the growth, development, and functioning of that organism. Genomes are made up of DNA (deoxyribonucleic acid), which is organized into structures called chromosomes. Each species has a unique genome that determines its characteristics. In humans, the genome consists of about 3 billion DNA base pairs and contains approximately 20,000 to 25,000 genes. The study of genomes is known as genomics, which helps scientists understand genetic diseases, evolution, and biodiversity. Advances in DNA sequencing technology have made it easier to analyze and compare genomes across different species.