2. what is the factor in an experiment that a scientist wants to observe, which may change in response to the manipulated variable; also known as a dependent variable​

they are made of gases.

they have a spherical shape.

they make energy through fusion.

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.