Cellulose, a complex carbohydrate and the primary constituent of plant cell walls, is crucial for maintaining structural integrity in plants. It doesn't "cross a line" in a literal sense but is found extensively across various biological and industrial applications due to its unique properties such as biodegradability and high tensile strength. In the context of environmental concerns, cellulose-based products are often viewed as sustainable alternatives to synthetic materials. However, the extraction and processing of cellulose, especially from wood, can have environmental impacts, including deforestation and chemical pollution. Thus, while cellulose serves essential functions and offers environmental benefits, its production and use must be managed responsibly to minimize negative impacts.

To unlock the ability to change your Palico's armor pigment in Monster Hunter games, particularly titles like Monster Hunter World and its expansion, Iceborne, you initially need to progress through the main storyline. Typically, the option becomes available once you reach a certain Hunter Rank (HR) or after completing specific key quests, which often involves defeating a major monster or reaching a new area in the game. In Monster Hunter World, for instance, the feature is unlocked after you've progressed past the low-rank quests and enter the high-rank quests. Make sure to check the Smithy or your room's Housekeeper in-game, as these are the places where you can customize your Palico's gear. Keep advancing through the story, and pay attention to any notifications or new options that become available at the Smithy, as these will indicate when you've unlocked new customization features, including armor pigment changes for your Palico.

Ion pigments, commonly used in semi-permanent hair coloring, can have varying longevity depending on various factors including hair structure, the specific color used, and maintenance routine. On average, Ion color brilliance can last between 4 to 6 weeks. However, this timeframe can be extended with proper hair care. Using color-protecting shampoos and conditioners, washing hair with cooler water, and minimizing the use of heat styling tools can help in maintaining the vibrancy of the color for a longer period. It is also essential to follow the application instructions carefully and use a color sealer after coloring. The effects of ion pigments can diminish faster with frequent washing or exposure to harsh environmental conditions.