Final answer:
Cellular respiration is an open system as it exchanges gases and energy with the environment, making option A the correct choice. It involves transforming glucose and oxygen into carbon dioxide, water, and ATP through a series of metabolic reactions.
Step-by-step explanation:
Cellular Respiration as an Open System
Cellular respiration is a biological process in which living organisms take in oxygen and glucose, converting them into carbon dioxide, water, and ATP (adenosine triphosphate). Given that the reactants are taken from and the products are released into the environment, this process exemplifies an open system. Such a system allows both energy and matter to be transferred between the system (the organism) and its surroundings.
In an open system, organisms exchange materials and energy with their environment. As the student's description outlines, through cellular respiration, glucose (C6H12O6) and oxygen (O2) are converted into carbon dioxide (CO2), water (H2O), and ATP—the cell's energy currency. Importantly, this process requires the cooperation of various organ systems, including the digestive system for glucose, and the respiratory and cardiovascular systems for oxygen transport.
Therefore, when considering the definition and characteristics of systems, cellular respiration is most accurately categorized as an A. Open system. It is not a closed system, as it does not isolate its internal processes from the external environment. Nor is it exclusive to any subset of organisms, as it occurs in both autotrophs and heterotrophs—though the former can produce their own food through processes like photosynthesis, while the latter must consume organic material to obtain glucose.