【单选题】Lichens To be certain, a lichen is not the most conspicuous of plants. Lichens grow in unassuming fashion on rocks, logs and other exposed suces in a wide range of habitats around the world. To the...
A.
Very little is known about the internal structure of lichen.
B.
The true nature of lichen is not readily apparent.
C.
Lichen is the only composite plant known to exist.