Question 2 of 13 - U-Science-Gr6-Unit5-PBT-CBT (2020-21)
Question: 1
Based on the diagram of the hierarchical organization of a domestic cat, which level of organization is missing from the diagram below?
cat
circulatory
heart
muscle
blood cell
atom

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.