A lichen is a symbiosis of algae and fungi, and requires light as a source of energy in order to build up chlorophyll by photosynthesis, a typical feature of algae.
(A lichen; is; a symbiosis of algae and fungi) (A lichen; requires; light; as a source of energy in order)
A lichen A lichen
is requires
a symbiosis of algae and fungi
light as a source of energy in order