The answer is A. Isotopes only differ in the number of neutrons in the nucleus of their atoms. Otherwise, all other subatomic particles are the same. The isotope with the more neutrons in its nucleus is therefore, heavier (have higher mass number). They share the same chemical properties but have slight physical differences such as boiling points with the heavier element having a slightly higher boiling point that the lighter element.
True. Each contour line on a topographic map represent a certain elevation; the closer they are, the steeper the surface is. All points on a contour line are the same elevation.
<span>identify the order in which rock units formed</span>