Name the following:

A solution used to store biological specimen.

1. Preservatives are used to store the substances to delay their degradation.
2. Biological specimens are stored for many years in bottles filled with Formalin.
3. Formalin is the mixture of $(30-40\%)$ water in formaldehyde ($\mathbf{HCHO}$).
4. Hence, a solution used to store biological specimen is Formalin.