Each element on the periodic table is represented by a:

Each element on the periodic table is represented by its element symbol and atomic number.

Explanation:

The periodic table is the list of known chemical elements. The atomic number of an element is the same as the number of protons in the particular nucleus of an atom.

The elements in the periodic table are arranged into periods and groups. A row of elements across the table is called a period.

In a periodic table element is listed by its symbol and atomic number. For example "H" denotes hydrogen, "Li" denotes lithium.

The elements in the same group represents the patterns in atomic radius, ionization energy and electronegativity. The elements are represented by 2 letters one capital and other in lower case. they are arranged based on the increased atomic number.

answer: b: experiments that showed that all cells are similar in how they metabolize and in their composition

explanation: