1. all fungi are
a.) photosynthetic
b.) heterotrophic
c.)autotrophic
d.) parasitic
2. the tangled mass that makes up part of the fungi that is below the soil is the
a.) mushroom
b.) fruiting body
c.) mycelium
d.) chitin
3. what structure is missing in the fungal hyphae shown on the right side of figure 21-5?
a.) cells walls
b.) cross walls
c.) nuclei
d.) cytoplasm.
4. an important role of fungi in an ecosystem is
a.) performing photosynthesis
b.) breaking down dead organisms
c.) making alcohol
d.) killing bacteria
5. how do yeast reproduce?
a.) sexually by producing spores
b.) asexually by producing spores
c.) sexually through binary fission
d.) asexually through binary fission

1. B - heterotrophic

All fungi are heterotrophic mainly because they rely on the external sources in obtaining organic material. They do not produce their own food, so they are not autotrophic like plants. They do not manufacture their food from light so they are not phototrophic. They are parasitic but not always.

2. C. Mycelium

Mycelium look like a tangled mass of threads. It is used for the absorption of food from external sources. Their high surface volume ration allows them to get enough nourishment.

3. B. Cross walls 

Fungal hyphae are divided internally by "septa". These septa are called cross-walls. These septa usually have pores that allow ribosomes and mitochondria to flow between the cells.

4. B. Breaking down dead organisms. 

Fungi are decomposers. They break down dead organisms and this helps because the organic matter that is decomposed by fungi can be used by other decomposers and can be used as food for plants. 

5. B. Asexually by producing spores

Yeast produces asexually either through budding of spores and by fragmentation as well. The spores they bud are called conidiospores. The reproductive structures are the asci, which is the sexual spore-bearing cells, that form on the end of specialized hyphae.