In an Attempt to Determine the Source of a Growing

Multiple Choice

In an attempt to determine the source of a growing plant's mass, van Helmont planted a willow seedling in a pot of soil. After five years, the willow weighed 76.8 kg, and the soil had lost 0.06 kg of weight. Only water had been added to the pot. Which of the following conclusions should van Helmont have drawn?

A) Plants get their mass from water.
B) Plants get their mass from water and air.
C) Plants get their mass from water and atmospheric CO₂.
D) Plants get all or almost all of their mass from a source other than soil.