In our lungs series we continue to encourage ways for us to strengthen the immune system as prevention is the best "medicine." Ms. Karon gives some more insight on the power of Vitamin D while also sharing benefits of vitamin K2 and vitamin A. Do you remember that our immune system is an army? We learn that the thymus gland is the traning camp for our army. We also talk about zinc and find out why sometimes we need to "mega dose" if we have quality, food-based suppliments.