Final answer:
Respiration in root cells releases CO2, which can decrease soil pH and increase the availability of cations for root absorption, thereby supporting plant nutrition.
Step-by-step explanation:
The correct answer to the question is A. True. Respiration in root cells can lead to a decrease in the pH levels of the soil around the root hairs. This occurs due to the release of carbon dioxide (CO2), which reacts with water to form carbonic acid, subsequently releasing hydrogen ions (H+) and lowering the soil pH. A lower pH can result in cations like potassium (K+), magnesium (Mg2+), and calcium (Ca2+) becoming more available for absorption by the root cells. These nutrients are crucial for plant growth and development. Hence, respiration in root cells plays a role in making cations available in the soil for plant uptake.