Im guessing the increase of GMO foods and excess preservatives and chemicals that may provoke certain food intolerances and allergies.
Yeast has many comercial uses in the production of breads, fuel, sodas, and wine.
Answer:
Natural immunity occurs when you become immune to a specific disease after contracting it. This triggers your immune system to make antibodies against the germ causing the infection inside of you. Antibodies are like special bodyguards that only recognize certain germs.
