Which of the following pathogens is one of the exceptions to the rule of typical cell structure?
a. bacteria
c. fungus
b. viruses
d. protists

The correct answer is B) Viruses.

Virus is a pathogenic agent having an exception to the rule of typical cell structure. Viruses do not possess any cytoplasm, nucleus, or organelle like a typical cell.

Viruses are therefore considered as non cellular particles, which are also called non living particles. They can replicate their DNA only when enter a host cell.

Thus, they are one of the exceptions to the rule of typical cell structure.

a physical change is being made.