What type of bacteria is rod-shaped and known for causing diseases such as tetanus and tuberculosis?

The correct choice indicates that bacilli are rod-shaped bacteria. Bacilli are classified as one of the primary shapes of bacteria, which also include cocci (spherical) and spirilla (spiral). Rod-shaped bacteria, such as those in the bacilli category, include well-known pathogens like Clostridium tetani, which causes tetanus, and Mycobacterium tuberculosis, the causative agent of tuberculosis. Recognizing the shape of bacteria is crucial in microbiology, particularly in understanding how they can impact health.

In contrast, diplococci refers to pairs of cocci, typically spherical bacteria, and is associated with infections such as pneumonia and gonorrhea. Streptococci consist of chains of cocci and are involved in various diseases, including strep throat and scarlet fever. Spirilla, characterized by their spiral shape, can be associated with specific diseases such as syphilis and Lyme disease. Understanding these distinctions is fundamental for determining how different types of bacteria can affect human health.