I don't fully understand your question, but I believe that plants have functions that are vital to the planet. They take sunlight, make it into food for themselves, and release oxygen that we need to survive.
Answer:
1. C + O₂ → CO₂
2. C + CO₂ → 2 CO
3. Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂
Answer:
rows
Explanation: periods are ROWS that run from left to right.