Final answer:
Bordetella pertussis, the bacteria that causes pertussis, is a gram-negative coccobacillus, meaning it is short, round, and rod-shaped.
Step-by-step explanation:
The shape of Bordetella pertussis, the bacteria that causes pertussis (whooping cough), is a gram-negative coccobacillus. A coccobacillus is a type of bacteria that is short, round, and rod-shaped, with a length slightly greater than its width. It is often described as a combination of a spherical (coccus) and rod-shaped (bacillus) bacterium. The gram-negative classification refers to the bacteria's ability to retain a specific type of stain during the Gram staining process.