Read the given passage and answer the questions that follow.

The extraction of indigo dye involves harvesting the green leaves of the Indigofera plant prior to its flowering stage, and then soaking these leaves in water followed by churning until a navy blue froth appears. The upper portion of the resulting mixture is drained to be used for irrigation, while the remaining leaves are converted into fertilizer. After allowing the water and fine sediment to settle for a day, the liquid is separated from the sediment, yielding a deep blue paste. This paste undergoes filtration to remove any dirt and impurities, and is then compressed into cakes and dried for several days until it is ready for use as dye. The addition of lime (Ca(OH)₂) to the water and leaves mixture, as well as the dissolution of various natural sugars into the paste, can enhance the extraction process.