Question

When a tree grows to an impressive height, it has concentrated a great deal of mass into its tissues. Where does most of the material in the tree come from?

	A.	water from the soil
	B.	minerals in the soil
	C.	oxygen from photosynthesis
	D.	energy from the Sun
	E.	CO2 in the air

Answer 1

When a tree grows to an impressive height, it has concentrated a great deal of mass into its tissues. Most of the material in the tree comes from CO2 in the air. Plants synthesize food through the process of photosynthesis. In this process, plants convert CO2 into the air into food (glucose) in the presence of energy from sunlight and water from the soil. They use some amount of food for meeting their energy needs through the process of respiration. They store remaining food into their tissues. Since the food was synthesized from CO2 in the air, most of the material in the tree comes from CO2 in the air.