Nuclear DNA is the genetic material found within the nucleus of eukaryotic cells. It contains the instructions for building and maintaining an organism, encoded in sequences of nucleotides. Each cell in an organism typically contains two copies of nuclear DNA, one inherited from each parent, which contributes to genetic diversity. This type of DNA is organized into structures called chromosomes, which are visible during cell division. In humans, there are 23 pairs of chromosomes, totaling 46. Nuclear DNA plays a crucial role in processes such as cell division, inheritance, and protein synthesis, making it essential for life.