Final answer:
An organism that requires the presence of oxygen to live is known as an obligate aerobe, relying on it for aerobic respiration and possessing enzymes to mitigate oxidative stress from reactive oxygen species.
Step-by-step explanation:
The name given to a microorganism that can exist only in the presence of oxygen is obligate aerobe. These microorganisms are utterly dependent on aerobic respiration and utilize oxygen as a terminal electron acceptor in their metabolic processes. Humans, for example, are obligate aerobes, and so are some bacteria, like Mycobacterium tuberculosis, which causes tuberculosis (TB). Obligate aerobes contain enzymes like peroxidase, superoxide dismutase, and catalase to defend against the reactive oxygen species (ROS) that occur as byproducts of using oxygen in respiration.