<span>It is true that walking to work is one way of helping improve air quality. If you are walking, or riding a bicycle to your work, you are obviously not using a car or a bus which use fuel which pollutes air. So, if more people would do this, they would help improve their living conditions and the air we breathe, because each day, our air becomes more and more polluted. </span>
Bacteria, molds and yeast are the most important microorganisms that cause food spoilage and also find the maximum exploitation in production of food and food products. Different strains of bacteria and fungus are used for fermentation of dairy products for production of a wide variety of cultured milk products.
No, it's because we need to breathe. Your body needs oxygen. Air pressure has little to nothing to do with it as far as I know.
The answer will be both A and B