How Plants Live 
31 
The energy of the sunlight, 
oxygen for respiration, and car- 
bon dioxid for photosynthesis 
are received by the leaves. 
Water vapor, oxygen from pho- 
tosynthesis, and carbon dioxid 
from respiration are given off 
by the leaves. 
The stem transports ma- 
terials between the leaves 
and the roots. Water and 
taw food materials pass up | 
to the leaves, and food 
passes down from the 
leaves to the roots. 
Oxygen, water, and raw food ma- 
terials that are dissolved in the 
soil water are taken in by the 
roots. 
Carbon dioxid is given off by the 
roots. Probably substances that 
help to dissolve raw food mate- 
rials in the soil are also given off. 
Fic. 24. Diagram illustrating the work of the different parts of a plant. 
