Defend
Look at a nature survivalist, rancher twins, a doctor who survived Ebola and the recipient of a cutting-edge cancer therapy to uncover the wildly advanced biology that keeps us alive against all odds.
Previews + Extras
Episode 4 Preview | Defend
S1 E4 - 30s
Look at a nature survivalist, rancher twins, a doctor who survived Ebola and the recipient of a cutting-edge cancer therapy to uncover the wildly advanced biology that keeps us alive against all odds.
The Immune System
S1 E4 - 2m 6s
An introduction into the amazing functions of the human body's immune system.
Similar Shows
When Disaster Strikes
Science and Nature
BrainCraft
Science and Nature
Human Footprint
Science and Nature
Humanity from Space
Science and Nature
Beauty on the Wing: Life Story of the Monarch Butterfly
Science and Nature
WETA Passport
Stream tens of thousands of hours of your PBS and local favorites with WETA Passport whenever and wherever you want. Catch up on a single episode or binge-watch full seasons before they air on TV.