The second line of defence is a group of cells, tissues and organs that work together to protect the body. This is the immune system.
When a pathogen (disease-causing organism) invades the body, the neutrophils gather at the entry site and try to engulf it and destroy it.
A T helper cell will recognise only one pathogen. If the T helper cell recognises the invader, it will immediately clone to increase numbers.
After a few days of fighting off the pathogen, you will recover from your infection.
<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>
Watching/looking out for the early syntoms.
