Filaments of Spirogyra placed in a beaker of water in a dark cupboard died because
Answer Details
Filaments of Spirogyra placed in a beaker of water in a dark cupboard died because the filaments could not photosynthesize. Photosynthesis is the process by which green plants, including Spirogyra, convert light energy into chemical energy in the form of glucose. This process requires light, which was absent in the dark cupboard. Without light, the Spirogyra filaments could not produce the food they need to survive, and they eventually died. Conjugation, temperature, and flooding would not have directly caused the death of the Spirogyra filaments in this scenario.