A chromosome is a long, thread-like structure made of DNA and protein that carries genetic information. Humans typically have 46 chromosomes, organized into 23 pairs, with one set inherited from each parent. Chromosomes play a crucial role during cell division, as they ensure that genetic material is accurately replicated and distributed to daughter cells. They are essential for maintaining genetic continuity and influencing traits and characteristics in organisms. Chromosome abnormalities can lead to genetic disorders and diseases, highlighting their importance in both genetics and health.