Cryopreservation is a process that involves cooling and storing cells, tissues, or even whole organisms at very low temperatures to preserve them for future use. This technique is commonly used in biology and medicine to save valuable samples, such as human sperm, eggs, and embryos, allowing for assisted reproductive technologies like in vitro fertilization (IVF). The cooling process slows down cellular metabolism and prevents damage from ice crystal formation. By using liquid nitrogen, which can reach temperatures as low as -196 degrees Celsius, scientists can maintain the viability of these biological materials for years, ensuring they remain intact for research or medical treatments when needed.