There's a version my brother, the physics professor, liked to reference.

Tell me why the stars do shine;
Tell me why the ivy twines?
Tell me why the sky's so blue?
And I will tell you just why I love you!

Nuclear fusion makes the stars to shine.
Heliotropism makes the ivy twine.
Rayleigh scattering makes the sky appear blue.
Testosterone-induced hormonal response is why I love you!

(last line has to be intoned really fast to fit the meter).