And the Award for "Best Opening Sentence in an Abstract Goes To . . ."

There are generally four types of opening sentences in research paper abstracts:

1. A statement of a real-world phenomena or a standard practice.
2. Stating a purpose or an objective.
3. A statement presenting current research action. 
4. Stating a problem or uncertainty. 

And then there is a fifth kind of opening sentence in a research paper abstract, exemplified by the zinger below:

Ducks are birds. 

Someone please give the author his much-deserved award!