They are called isotopes.
Example of isotopes are Hydrogen and deuterium.
Hydrogen is 1 proton and 0 neutrons.
Deuterium is 1 proton and 1 neutron
Well, TECHNICALLY, the periodic table is "based" upon a whole myriad of characteristics. But if you're talking about the consecutive arrangement of elements...it would be B, the atomic number.
Answer:
Unicellular organisms achieve locomotion using cilia and flagella. By creating currents in the surrounding environment, cilia and flagella can move the cell in one direction or another.
Explanation:
