AP BIOLOGY

Detailed explanation-1: -So where does the mass come from? The mass of a tree is primarily carbon. The carbon comes from carbon dioxide used during photosynthesis. During photosynthesis, plants convert the sun’s energy into chemical energy which is captured within the bonds of carbon molecules built from atmospheric carbon dioxide and water.

Detailed explanation-2: -Save this answer. Show activity on this post. The vast majority of a tree’s carbon comes from the air, which averages 0.03-0.04% by volume (300-400 ppmv) CO2. This is fixed through photosynthesis and eventually stored as glucose which the plant can then use for its metabolism.

Detailed explanation-3: -Plant growth is one way to teach students that most of the mass of the plant comes from somewhere other than the soil, but mostly in carbon dioxide and hydrogen atoms from water.

Detailed explanation-4: -Water, which can make up to 95% of the weight of a plant, enters the plant through its roots.