Your body's first defence is to try to keep everything out. Crying and coughing is just a way to keep pathogens (bad germs/ bacteria) out. Your skin is another barrier that can help keep germs out. The skin even has a tiny bit of acid to kill some pathogens!
Yes, they are even more important!
Are there anymore defence systems?
The second line of defence can cause fevers, colds and other symptoms to arise . Your body is only reacting to the leukocytes (white blood cells) being sent to attack the pathogens.
Okay... I understand the first two but, how do I get better? How many leukocytes are there?