The chemical energy is then used by the plants to perform a variety of functions including the production of plant 
(The chemical energy; is used; by the plants; to perform a variety of functions including the production of plant; T:then) (The chemical energy; to perform; a variety of functions including the production of plant)
The chemical energy The chemical energy
is used to perform
by the plants to perform a variety of functions including the production of plant T:then
a variety of functions including the production of plant