3. What happened to the carbon atom when it entered the plant through the stoma on the leaf? A. It moved from a sugar molecule to a carbon dioxide molecule.
B. It moved from a gas molecule to a protein molecule.
C. It moved from a carbon dioxide molecule to a sugar molecule.
D. It remained a carbon dioxide molecule in the leaf.

Reproduction i think

Lipid because of the high percentage of carbon to carbon bonds, which store more energy than other bonds.

By water evaporation from the leaves is created a negative pressure at the top of the tree that promotes the ascension  of the water through channels that are called xylem. there are also two molecule forces that are involved: the intra-water molecules cohesion (water molecules stick to each other) and the adhesion when the water molecules stick to the channels they are running in. this is what enables water to go from the roots to the top of a tall tree.