Atomic weight
one of two or more atoms of the same element with different masses due to different numbers of neutrons
2. isotope
a horizontal row on the periodic table
3. period
something that repeats itself on a regular, predictable basis
4. periodic
the average relative mass of each element

1. atomic weight - the average relative mass of each element

2.  isotope - one of two or more atoms of the same element with different masses due to different numbers of neutrons

3.  period - a horizontal row on the periodic table

4. periodic - something that repeats itself on a regular, predictable basis

Explanation:

4. periodic - something that repeats itself on a regular, predictable basis

2.  isotope - one of two or more atoms of the same element with different masses due to different numbers of neutrons

3.  period - a horizontal row on the periodic table

1. atomic weight - the average relative mass of each element

there is no

explanation:

primary succession occurs in essentially lifeless areas regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier. secondary succession occurs