Which process is primarily responsible for the production of \( \mathrm{CO}_2 \) that root hairs release into the soil?

• A. Transpiration
• B. Photosynthesis
• C. Nitrogen fixation
• D. Cellular respiration

Answer: (D)

Verified step by step guidance

1. Understand the role of root hairs: Root hairs are extensions of root epidermal cells that increase the surface area for absorption of water and nutrients. They also release carbon dioxide ( ${\mathrm{CO}}_2$ ) into the soil.
2. Recall the process of cellular respiration: Cellular respiration is the metabolic process by which cells convert glucose ( ${CHO}_6$ ) and oxygen ( $O_2$ ) into energy (ATP), water ( ${HO}_2$ ), and carbon dioxide ( ${\mathrm{CO}}_2$ ). This process occurs in the mitochondria of cells.
3. Connect cellular respiration to root hairs: Root hairs perform cellular respiration to generate energy for their metabolic activities. During this process, carbon dioxide ( ${\mathrm{CO}}_2$ ) is produced as a byproduct and released into the soil.
4. Differentiate cellular respiration from other processes: Transpiration involves the movement of water through plants and its evaporation from leaves, while photosynthesis uses carbon dioxide ( ${\mathrm{CO}}_2$ ) to produce glucose. Nitrogen fixation is the conversion of nitrogen gas into ammonia by certain bacteria. None of these processes directly produce carbon dioxide ( ${\mathrm{CO}}_2$ ) as a byproduct in root hairs.
5. Conclude that cellular respiration is the correct answer: Cellular respiration is the primary process responsible for the production of carbon dioxide ( ${\mathrm{CO}}_2$ ) released by root hairs into the soil.