Biology高手，請........（20點）

I am surely not good in biology .Since nobody answer your question , I would like to try .
1. Through years of years evolution , human body adapts to code with the change so they can survive .
2. There are plenty of small living organism around us that they are so tiny required microscope to veiw . There are 2 classes , one is good for us & one will hurt us . The bad one can infect our bodies causing diseases . Due to the invasion of bacteria or virus , our bodies usually have white blood cell to defend & finally eliminate the invaders . If our body is healthy enough , we win the battle , or we need to see the doctor to use antibody to kill them .
3. I donot quite understand this question . When infavour conditions lasted , such dry around , let take mould for example , they will form spores floating in the air , when they touch humid & warm area , they germinate & feed on the substrate to form a lot of mould .
4. This is because each indivual will encount different enviroment so the adaptation is quite different . So through years of change , there are variations happened on each indivual even within the same species .