What happens during the process of respiratory acidosis?

During respiratory acidosis, there is a retention of carbon dioxide (CO2) in the body. This condition typically arises when the lungs are unable to excrete CO2 effectively, leading to an accumulation of this gas in the bloodstream. As CO2 levels rise, it combines with water to form carbonic acid, ultimately resulting in decreased pH levels, which characterizes acidosis.

In contrast, the other choices do not accurately reflect the mechanisms involved in respiratory acidosis. Rapid excretion of CO2 would actually lead to an increase in pH, and a decrease in carbonic acid levels is not associated with this condition. Additionally, an increase in pH levels is not characteristic of respiratory acidosis; rather, the pH falls due to the excess carbonic acid produced from the retained CO2. Hence, the process of respiratory acidosis is primarily defined by the retention of CO2, leading to its effects on acid-base balance in the body.