Which component of soil contributes gases necessary for plant growth?

The correct answer highlights the critical role of air in soil, particularly in relation to providing essential gases for plant growth. Soil air contains important gases, including oxygen and carbon dioxide, which are vital for various processes.

Oxygen is crucial for root respiration, enabling plants to convert nutrients into energy. Without sufficient oxygen in the soil, root systems may struggle to grow and function effectively. Meanwhile, carbon dioxide produced by soil microorganisms is also important for photosynthesis, a process that allows plants to produce their food and release oxygen into the atmosphere.

The composition of air in the soil is influenced by the balance of soil moisture and organic material, but it is specifically the air that supplies the necessary gases directly involved in plant physiological processes. Hence, while other components like minerals, organic material, and moisture are important for overall soil health and plant growth, it is the air that directly contributes the gases needed for the respiration and photosynthesis necessary for plants to thrive.