Carbon-12 and Carbon-14 are considered
of each other.

The direct answer is that they are Isotopes of one another.

Explanation:

isotopes

Explanation: Isotopes are atoms of the same element having the same atomic number but different atomic masses. Atomic number of an element is the number of protons contained in the nucleus of an atom. Atomic mass is the sum of the protons and neutrons in the nucleus of an atom.

The difference in the atomic masses is due to the number of neutrons in the atoms. This isotopes have the same number of protons but different number of neutrons. The phenomenon whereby atoms of the same element have the same atomic number but different mass number is called isotopy.

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.

the awnser is group 12