Drag is another one i actually did this project in 5th grade so i know some of this hope this helps.
Photosynthesis is used by plants for energy. In addition to carbon dioxide and water, light and chlorophyll are required for photosynthesis to work.
Human can produce a maximum mechanical power of 1/3 hp (horse-power).
Horse power is a unit of power, it equals 746 watt (watt is also a power unit, known to be equal to a joule per second)
So:
1 ph = 746 watt = 746 J/s
1/3 ph = 248.6 J/s
we're looking for the calories, so
1 joule = 0.239006 calories
So human produce a maximum mechanical power of:
248.6 J/s = 82.88 calories per second.
We're looking for the number of calories consumed in three hours, so:
82.88 cal/s = 82.88 cal/s * 3600 s * 3 = 895200 calories = 895.2 kilocalories (food calories).
The number of food calories is 895.2 food calories
Its C. Whenever you perform an experiment you want to make sure its as controled as it can possibly be.