How did seedless vascular plants affect atmospheric CO₂ levels during the Carboniferous period?

• A. They decreased CO₂ levels by fixing carbon, leading to global cooling
• B. They caused an increase in methane, altering CO₂ indirectly
• C. They increased CO₂ levels by releasing it during respiration.
• D. They maintained CO₂ levels, preventing climate change

Answer: (A)