The correct option is D.
Cellular respiration is the process by which the body breaks down the sugar molecules that are eaten in food with the aid of oxygen and covert them into energy, carbon dioxide and water are also produced as by products. Cellular respiration and fermentation are both involved in the breaking down of sugars but cellular respiration occurs in the presence of oxygen while fermentation occurs in the absence of oxygen. Carbon dioxide is breath out by the lungs during cellular respiration.
Bacteria that change nitrogen gas from the atmosphere into solid nitrogen usable by plants are called nitrogen-fixing bacteria. These bacteria are found both in the soil and in symbiotic relationships with plants.
Answer:
Number 4 here.click on the picture
In the world's oceans 90% of the biomass is microbial with viruses turning over 20% of that daily. without the turnover of biomass driven by viruses many sources of food would not be present for other organisms