The skin is an example of a non-specific defense.
For example, bacteria or diseases have trouble entering a healthy person's skin because it is formed by closely packed cells with multiple layers and a substance called keratin that protects is.
On the other hand, the immune system is a specific defense mechanism.
When bacteria is able to enter the body in cases of fever for example, the immune system is activate and sends out protector cells such as the white blood cells to combat infection.
Yes I agree with that statement you just said there and I think you should become president for it, good job comrade.
Competition is the answer
It depends on whatever it's real or just a simple theory. But, at times it may not be simple as it seems, because theories are often left as theories. In the near future (or even now) they'll be testing to see if theories can be proven as a fact!
Good luck!