I believe the answer is B, although A has as well a very good chance of being correct. But B does support evidence with the chemicals found inside them.
That the tree is not as old than a tree with thicker rings because the tree has had more time to absorb the water.
Most fungi are multicellular organisms. They display two distinct morphological stages: the vegetative and reproductive. The vegetative stage consists of a tangle of slender thread-like structures called hyphae (singular, hypha), whereas the reproductive stage can be more conspicuous. The mass of hyphae is a mycelium
This is a biome.
Biomes really do cover large areas, for example there is one biome stretching from France to central Russia (temperate broadleaf forrest). They are characterized by a similar soil and a shared community of animals and plants.