Given a scientific question, generate a correct answer to it.
--------
Question: Exemplified by cesium, which ignites spontaneously in air, pure elements with a high metallic character tend to be very what?

Answer: reactive

Question: Bog destruction in scotland is an example of the widespread loss of what kind of habitat?

Answer: wetland

Question: What natural process allows water to return again to the earth's surface?

Answer:
precipitation