'biological functions' is correct and can be used in written English.
Example sentence: Through natural selection, species can evolve to better perform their biological functions.
(See below Biological functions of lipids).
Most basically there are the biological functions.
The dividend here is not pleasing public spaces but insights into biological functions, disease and agriculture.
Stories serve important biological functions, this insightful book claims.
His work as a cell biologist has centered on genetics and the use of genetic methods to understand biological functions.
In the next two to three years, patients will be able to record biological functions automatically through apps.
This technique is called synthetic biology and it combines science and engineering to build new biological functions and systems.
Of course, it's perfectly possible that statins can improve some biological functions associated with aging and worsen others.
Lead has no known biological functions.
These enzymes perform many important biological functions.
Talk of biological functions often has a teleological flavor.
