Occam's Razor:
Fred the Oyster, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Further energetics:
© LibreTexts - https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_Chem1_(Lower)/15%3A_Thermodynamics
_of_Chemical_Equilibria/15.04%3A_Free_Energy_and_the_Gibbs_Function

Further redox:
© LibreTexts - https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Supplemental
_Modules_(Analytical_Chemistry)/Electrochemistry/Voltaic_Cells

Further kinetics:
https://commons.wikimedia.org/wiki/File:Activation_energy.svg#file

Modern analytical techniques (the isotope):
Johannes Schneider, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons