No, it is caused by an infection or when your body decides it needs to "starve off" foreign substances.
Yes Bacterial infection may cause fever and it is indication that body has some alien attack, as fever is not a disease but an indication that body has been attacked by either bacteria or virus and...
Not always but it is likely
Yes. In fact fever is a classic symptom of the flu, which is caused by a virus. These fevers generally range from 100-103 degrees F.
The fever is hot so that it can burn and get rid of the infection.