An increase in human-made carbon dioxide in the atmosphere could initiate a chain reaction between plant and microorganisms that would unsettle one of the largest carbon reservoirs on the planet soil in a study, it was found that the soil, which contains twice the amount of carbon present in a plants and Earth's atmosphere combined, could become increasingly volatile people add more carbon dioxide to the atmosphere. This is largely because of increased plant growth. Although a greenhouse gas and a pollutant, carbon dioxide also supports plant growth. As trees and other vegetation flourish in a carbon dioxide-rich future, their roots could stimulate microbial activity in soil that may in turn accelerate the decomposition of soil carbon and its release into the atmosphere as carbon dioxide. Which among the following is the most logical corollary to the above passage?

The passage describes a chain reaction: increased atmospheric carbon dioxide leads to increased plant growth (green cover). This increased plant growth, through root activity, stimulates microbial activity in the soil, which then accelerates the decomposition of soil carbon and its release into the atmosphere as carbon dioxide. Let's analyze the options: A) Carbon dioxide is essential for the survival of microorganisms and plants. The passage states CO2 "supports plant growth," not necessarily that it is "essential for survival" for plants, and it doesn't state it's essential for microorganisms' survival. This is an overstatement. B) Humans are solely responsible for the release of carbon dioxide into the atmosphere. The passage mentions "human-made carbon dioxide" initiating the process, but then describes a natural feedback loop where soil releases CO2. The word "solely" makes this incorrect. C) Microorganisms and soil carbon are mainly responsible for the increased plant growth. The passage states that increased plant growth is "largely because of increased carbon dioxide to the atmosphere." Microorganisms and soil carbon are affected by plant growth, not the primary cause of increased plant growth in this context. D) Increasing green cover could trigger the release of carbon trapped in soil. This directly aligns with the passage's explanation: "As trees and other vegetation flourish in a carbon dioxide-rich future... their roots could stimulate microbial activity in soil that may in turn accelerate the decomposition of soil carbon and its release into the atmosphere as carbon dioxide." "Flourish" implies increasing green cover, and the subsequent events describe the release of soil carbon. Therefore, D is the most logical corollary.