Correct Option
The correct option is Spirogyra.
Explanation
Asexual reproduction allows a single organism to produce offspring without the fusion of gametes. Different organisms employ specific mechanisms such as fission, budding, spore formation, regeneration, and fragmentation depending on their body organization and complexity.
Detailed Analysis
- Spirogyra (Correct): Spirogyra is a multicellular alga with a simple body structure. It reproduces through a process called Fragmentation. Upon maturation, the filaments of Spirogyra simply break up into smaller pieces or fragments. Each of these fragments then grows into a new individual.
- Hydra: Hydra primarily reproduces by Budding. In this process, a bud develops as an outgrowth due to repeated cell division at a specific site. While Hydra also possesses the ability to regenerate if cut, it does not naturally break into fragments upon maturation as a primary reproductive strategy.
- Planaria: Planaria is the classic example of Regeneration. If the organism is accidentally cut or broken into many pieces, each piece can grow into a complete organism. However, regeneration is generally considered a survival mechanism against injury rather than a reproduction method triggered by maturation.
- Rhizopus: Also known as bread mould, Rhizopus reproduces via Spore Formation. It develops sporangia (blob-like structures) that contain spores, which are released to germinate into new individuals under favourable conditions.
Key Takeaway
Fragmentation is the specific mode of asexual reproduction where an organism (like Spirogyra) breaks into pieces upon maturation to form new individuals. This is distinct from Regeneration (Planaria), which is typically a response to injury, and Budding (Hydra/Yeast).