<span>Infection is the term used to describe the process through microorganisms that cause diseases. The invasion of a host by a pathogenic microorganism multiplies in the tissues and the reaction of the host to its presence and to its possible toxins and can be caused by bacteria, fungi, viruses, protozoa or prions.</span>
Chemotrophs (Bacteria) are essential in the conversion of nitrogen containing compounds to nitrogen forms that are accessible and usable by plants.
The correct answer is A) cocci
Bacilli is common for everyone and even cocci are actually called coccobacillia. Cocci is circular.