Variations in the Earth's orbital rotation have caused major changes in the history of Earth's climate. These types of changes
are caused by
-natural processes.
-human activities.
-natural processes and -human activities.
-population cycles.

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.