Sheldon tells Penny that he is still interested in String Theory because it is elegant. He gives a brief explanation of it and states that scientists have been working on it for decades.

The group escapes from hepatitis B and enters Alveoli Forest, where they encounter the bronchial tubes, alveoli, and the disease, tuberculosis. Dr. Bloom explains that the human has latent tuberculosis, as the disease is usually found in many people's lungs but is not active. He changes his opinion, however, when he sees that tuberculosis bacteria has escaped from its inactive state.

Mitosis is a key function in your body that constantly remediates cuts, repairs cells and accomodates growth.   Key Words: Mitosis, Chromosomes, Diploid Cells, Haploid Cells, Prophase, Metaphase, Anaphase, Telophase, Centrosome Duplication, Chromatid, Centromere, Interphase 

Beakman covers hot springs and geysers and how they are used by people for electricity and to improve health. He shows some footage to explain how water in geysers is heated and shoots out of the Earth's surface.

Grover explains and demonstrates the concept of force by pulling a rope. He also illustrates how to influence force by inviting friends to pull the rope with him.