An ascus is _____.

• A. an asexual spore-producing structure on a stalk
• B. a club-shaped cell with spores on its outer surface
• C. a cup-shaped structure containing many spore-producing cells on the gill of a mushroom
• D. the sexual structure of chytrids
• E. a saclike structure containing spores

Answer: (E)

Verified step by step guidance

1. Begin by understanding the term 'ascus'. In biology, an ascus is a specialized cell found in fungi, specifically in the Ascomycota phylum.
2. Recognize that the ascus is a saclike structure. This is a key characteristic that differentiates it from other spore-producing structures.
3. Identify the function of the ascus. It is responsible for producing and containing spores, which are crucial for the reproductive cycle of the fungi.
4. Compare the ascus with other spore-producing structures mentioned in the options. Note that it is not a club-shaped cell, nor is it a cup-shaped structure on a mushroom gill, nor is it related to chytrids.
5. Conclude that the ascus is indeed a saclike structure containing spores, which aligns with the correct answer provided.