An example of a nonspecific defense provided by the skin is

a) antibodies.
b) fever.
c) proteins.
d) sweat.

The correct answer is- D) Sweat.

Non specific defense is a type of immune response ( also called innate immune response) that does not target any specific disease causing organism ( pathogen such as any specific bacteria or virus).

It is mainly provided by the surface of body ( such as skin that acts as an important barrier against external agents).

Sweat is an example of non specific chemical defense as it makes the surface of skin ( epithelium) acidic, thereby inhibiting the growth of pathogens ( such as bacteria) on it.

Thus, option D) is the right answer.