Final answer:
A dehydrated cell with a thick, shell-like wall in the context of fungi is known as a spore, which is a key reproductive unit that aids in the organism's survival and spread.
Step-by-step explanation:
A dehydrated cell with a thick, shell-like wall is known as a spore. In the context of fungi, spores are basic reproductive units that can withstand harsh conditions and facilitate the spread of the organism. The cell walls of fungi, which contain complex polysaccharides like chitin and glucans, provide structural support and protect the cells from desiccation and some predators. These walls are similar to plant cell walls but are distinct in their composition. Fungi are known for their reproductive structures like mushrooms, which are actually fruiting bodies responsible for producing spores. Essentially, spores are an adaptation that allows fungi to survive extreme environmental conditions and give the organism the ability to reproduce.