Given a scientific question, generate a correct answer to it.

Example Input: Exemplified by cesium, which ignites spontaneously in air, pure elements with a high metallic character tend to be very what?
Example Output: reactive

Example Input: What joins within each testis to form the epididymis?
Example Output: seminiferous tubules

Example Input: Millipedes and centipedes are the most commonly found examples of what group of arthropods?
Example Output:
subphylum myriapoda