Filamentous Structures: The filamentous structures present in the water are green algae (e.g., Spirogyra).
Reproduction: These green algae reproduce by fragmentation, which is a form of asexual reproduction. The filaments break into smaller pieces (fragments), and each fragment can grow into a new organism, thus increasing the population.
Explanation of the process: Fragmentation is a type of vegetative reproduction where each broken part of the organism can regenerate into a whole new individual. It helps in the rapid multiplication of algae in favorable conditions.
| Case No. | Lens | Focal Length | Object Distance |
|---|---|---|---|
| 1 | \(A\) | 50 cm | 25 cm |
| 2 | B | 20 cm | 60 cm |
| 3 | C | 15 cm | 30 cm |
Name the part performing the following functions in the human male reproductive system:
(a) Carries sperm
(b) Production of male gametes
(c) Whose secretion makes the transport of sperm easier
(d) Provides suitable temperature for sperm formation
Select the option having correct matching of the organism given in Column I with the mode of reproduction in Column II: Column I {0.2cm} 
Why are testes in human males located outside the abdominal cavity in scrotum?
| Case No. | Lens | Focal Length | Object Distance |
|---|---|---|---|
| 1 | \(A\) | 50 cm | 25 cm |
| 2 | B | 20 cm | 60 cm |
| 3 | C | 15 cm | 30 cm |