Operating for a relatively extended period of time.
(ux)
(quote-journal)
{{quote-journal|en|date=2021-04-21|author=Cara Giaimo|title=One of the World’s Oldest Science Experiments Comes Up From the Dirt|work=The New York Times|url=https://www.nytimes.com/2021/04/21/science/beal-seeds-experiment.html