Which one of the following is used for storing biological tissues?

Biological tissues are stored using liquid nitrogen (LN2) through a process known as cryopreservation [1]. Liquid nitrogen is considered the "gold standard" for long-term biosample storage because it maintains an extremely low temperature of -196 °C. At these cryogenic temperatures, cell metabolism and biological activity are effectively halted, which prevents degradation and maintains cellular integrity for extended periods [1]. This method is essential for archiving cells, tissues, and genetic samples in biobanks and research facilities. While mechanical freezers can reach -80 °C, liquid nitrogen is required to reach temperatures below the glass transition point of water (approximately -135 °C) to ensure maximum stability. Other substances like liquid bromine are not used for this purpose; bromine is an oxidizing agent and is typically liquid only at room temperature, not at cryogenic scales.

Sources

1. [1] https://en.wikipedia.org/wiki/Cryopreservation