Which compound can be used to preserve biological specimens?

Biological specimens have been preserved in alcohol and formalin for many years.This could damage the specimen and change the colour of the fluid.Engineered fluids are now used as a substitute for formalin as it is a more sustainable medium..Novec fluids which are low in toxicity are also used.

Nonmetals usually react by gaining electrons

Answerd. may include all of these are many definitions of bases: the  brønsted-lowry definition of acids and bases says that bases are proton acceptors.the arrhenius definition of acids and bases says that bases increase [oh⁻] in solution (thereby producing oh⁻ ions)the lewis definition of acids and bases says that bases donate electron pairs.therefore, the sensible answer is that a base may include all of the described characteristics.