Given a scientific passage and an answer, generate a question for the given answer.

Ex Input:
Passage: A metallic bond is the force of attraction between a positive metal ion and the valence electrons that surround itboth its own valence electrons and those of other ions of the same metal. The ions and electrons form a lattice-like structure. Only metals, such as the copper pictured in the Figure below , form metallic bonds. Answer: metallic bond

Ex Output:
What is the force of attraction between a positive metal ion and valence electrons?

Ex Input:
Passage: As you would expect, where plates collide there are lots of intense earthquakes and volcanic eruptions. The subducting oceanic plate melts as it reenters the mantle. The magma rises and erupts. This creates a volcanic mountain range near the coast of the continent. This range is called a continental arc . The Andes Mountains, along the western edge of South America, are a volcanic arc ( Figure below ). Answer: melts

Ex Output:
The subducting oceanic plate does what as it reenters the mantle?

Ex Input:
Passage: Xylem and phloem are the two types of vascular tissues in vascular plants. Answer: xylem and phloem

Ex Output:
What are the two types of vascular tissues found in vascular plants?