A chromosome is a long, thread-like structure made of DNA and proteins that carries genetic information. Humans typically have 46 chromosomes, organized into 23 pairs. Each chromosome contains many genes, which are segments of DNA that provide instructions for making proteins and determining traits. During cell division, chromosomes become tightly coiled, making them easier to separate. This process ensures that each new cell receives the correct number of chromosomes. Chromosomes play a crucial role in heredity, as they are passed from parents to offspring, influencing characteristics such as eye color and height through the genes they contain.