Bacilli are a type of bacteria characterized by their rod-like shape. They belong to the broader category of prokaryotes, which are single-celled organisms without a nucleus. Bacilli can be found in various environments, including soil, water, and the human body. Some bacilli are beneficial, while others can cause diseases. These bacteria can reproduce quickly through a process called binary fission, where one cell divides into two. Bacilli can also form spores, allowing them to survive in harsh conditions. Examples of bacilli include Escherichia coli, which is commonly found in the intestines, and Bacillus anthracis, the causative agent of anthrax.