The source of information was biased. It was like walking along a river bank in the country and asking everybody you meet whether they like fishing. Or asking 500 people sitting in the bleachers whether they like baseball.
I'm sure the scientist would have gotten different data if she interviewed 500 teenagers at neighborhood basketball courts, or 500 teenagers at a rock concert.
Answer is:
Photosynthesis transforms light energy into chemical energy. Cellular respration releasses the carbon dioxide from food into the air.
hope this helps :)
