posted by casey .
most of the total mass of a plant comesfrom which source?
Is is carbon dioxide?
Water comprises most of our mass too.
Carbon dioxide is one atom of carbon linked to two atoms of oxygen ("di-" means "two").
It is absorbed by plants and exhaled by animals.
I hope this helps. Thanks for asking.
Consider the molecular formula for glucose (other building blocks, such as other sugars, cellulose, and starches are similar ratios)
Notice there are 6H2O, and 6C
The water is about 1.5 massive as C. So most of the mass comes from water. Other molecules in plants have a similar ratio.