The Food of Piants 47 
The green plants can, 
therefore, build their 
sugar, fats, and proteins 
from substances which 
they take from the soil 
andair. They can build 
vitamins also, which it is 
believed an animal can- 
not do. So the green 
plants build out of sim- 
ple materials all the 
. complex foods used by 
the living matter of both 
plant and animal cells.! 
Plants can live without 
animals, but every ani- 
mal is dependent on 
plants for the food that 
keeps it alive. 
The manufacture of 
sugar. The first com- 
plete step in the manu- 
facture of food by the 
plant is the making of 
an . t 4X 
: MA > : . “e a 
Fic. 33. Without eating, the corn plant 
has lived, reached its full size, and at the 
end of its life has a surplus of food which 
it has stored in the ear. 
sugar. When light falls on 
the chlorophyll, carbon dioxid and water are combined 
within the cells to make sugar. This process is called 
photosynthesis (Greek, photos, meaning light, and syn- 
thesis, meaning a putting together). Photosynthesis 
1 Plants also build wood, cork, gums, waxes, and all the various other 
substances (excepting minerals) found in them. 
