Question

Plants use CO_​​2 for photosynthesis during the day . But at night , they also respire ,i.e.,take in O_{​​​​​​2} and release CO_{2​​​​} into the air . This doesn't help much in the reduction of CO_{​​​​​2} . Then why do people ask to plant more trees ? Is there a more effective method to reduce CO_{​​​​​2} in the air ?

Answer 1

At day time,trees use CO2 in atmosphere for photosynthesis and produce oxygen as a biproduct and also make glucose in food.So we get oxygen and food.
At night trees respire.They inhale mixture gases in atmosphere including oxygen and CO2.And use only oxygen and exhale CO2 that is inhaled
Thus trees do not increase amount of CO2.