Words similar to optional

Example sentences for: optional

How can you use “optional” in a sentence? Here are some example sentences to help you improve your vocabulary:

In addition, an optional user-defined energy threshold can operate in conjunction with the default threshold.
Finally, an optional 'user-defined sequence filter' simply eliminates the 70 mer candidates containing the defined sequences.
Participation was optional and informed consent was obtained for all interactions.
Optional: A gene tree based on the multiple alignment A and the query Q annotated with orthology bootstrap confidence values for the query Q .
The museum also boasts a natural history section, but, compared to the riches of the rest of the collection, this is entirely optional viewing.