Constantine reveals himself, showing his mole, which sets him apart from his doppelganger, Kermit.

Ed Walters speaks with Albert Einstein and mentions his theory of relativity. Einstein humbly says he too is still figuring out how his theories work.

Hank provides background information on the biologist who contributed to evolutionary history: Charles Darwin. He also explains the four principles of Darwin's idea of natural selection, which are variation, heritability, struggle for existence, and survival and reproduction rates. Key Words: Genetic Drift, Fitness, Variations of Phenotype, Heritable, The Struggle for Existence, Survival and Reproduction Rates

A short biography of Albert Einstein, German-born scientist who revolutionized the understanding of physics and the philosophy of science. This "Man of the Century" developed the theory of relativity and impacted the development of everything from lasers to cell phones.

Bill Nye narrates the story of how photosynthesis was discovered. He explains the hypothesis of the experiment that shed light on how plants generate energy.