The correct option is (a)
Explanation
Bread mould (commonly
Rhizopus) is a saprophytic fungus. It primarily propagates through
spore formation, which is a method of asexual reproduction. These spores are microscopic and ubiquitous in the environment.
Statement-wise Analysis
- Statement 1 is Correct: The cottony growth on bread originates from spores present in the air. These spores are lightweight and float freely; when they land on a suitable substrate like moist bread, they germinate and produce new hyphae (fungal threads).
- Statement 2 is Incorrect: The primary mode of reproduction for fungus growing on bread is asexual (via sporangiospores). While Rhizopus can reproduce sexually (via conjugation) under unfavourable conditions, the rapid colonization observed on bread is asexual. Additionally, sexual reproduction in this group involves gametangial copulation rather than the fusion of distinct, free-swimming gametes.
- Statement 3 is Incorrect: Spores are asexual reproductive bodies that possess a hard protective coating. This wall enables them to withstand unfavourable conditions such as high temperature, drought, and low humidity until they find a suitable moist surface to germinate.
Key Takeaway
Bread mould reproduces asexually through
spores found in the air. These spores are protected by a thick, resistant wall that allows them to survive harsh environmental conditions before germination.