Title: Planck constant.
Question: The mass of a resting body with what energy would be equal to a kilogram?

Title: Ashkenazi Jews.
Question: Who expelled the Jews from his Merovingian kingdom in 629?

Title: Flowering plant.
Question: What do the Wettstein and Engler systems use at the assigned rank of subdivision?

Title: United States dollar.
Question:
What is the British equivalent of a "buck"?