The inner planets are the planets before the asteroid belt. They are also closer to the Sun. The outer planets are the ones after the asteroid belt. <span />
Longitudinal waves have energy that vibrates parallel to the medium - a compression is the region of greatest density and the rarefaction the region of highest density .The rarefaction (much like the maximum amplitude in a transverse wave) has a region of lowest density, typically situated in the exact center of the region.
Answer:
c. selenium
Explanation:
sulfur and selenium are in the same group
