Polypropylene, a thermoplastic polymer commonly used in a wide range of applications due to its versatility and durability, can indeed develop cracks under certain conditions. Cracks in polypropylene typically occur due to environmental stress cracking (ESC), which happens when the plastic is exposed to certain chemicals, stress, or both. Additionally, exposure to UV light, extreme temperatures (both high and low), and physical impact can also make polypropylene more susceptible to cracking. Manufacturers often add stabilizers or use copolymers to enhance resistance to these factors, but it's essential to consider the specific environment and use case when selecting materials for applications requiring long-term durability.

Dietary fiber plays a crucial role in maintaining human health. Found in fruits, vegetables, whole grains, and legumes, it is best known for its ability to aid digestion by adding bulk to the stool, facilitating regular bowel movements, and preventing constipation. Additionally, fiber slows the absorption of sugar, helping regulate blood sugar levels, which is particularly beneficial for individuals with diabetes. It also binds to cholesterol in the digestive system, contributing to lower blood cholesterol levels and reducing the risk of heart disease. Fiber-rich diets are associated with a reduced risk of developing conditions such as obesity, stroke, and certain types of cancer. Further, high fiber intake provides a sense of fullness after meals, which can assist with weight management by reducing overall calorie intake. To glean these health benefits, it’s recommended that adults consume 25 to 38 grams of fiber per day, according to dietary guidelines.

Fluffy yarn is commonly referred to as "bouclé," "fuzzy," "fluffy," or "eyelash" yarn, each type having its unique texture and appearance. Bouclé yarn has loops that create a bumpy texture, while fuzzy yarns are covered in fine fibers that stand out for a soft, plush feel. Eyelash yarn closely mimics the appearance of fur, with long strands that resemble eyelashes, offering a unique texture perfect for crafting soft, visually interesting items. These yarn types are popular in making cozy sweaters, blankets, and novelty items due to their warmth and decorative appeal. Their fluffiness is typically achieved through the material used, such as mohair, alpaca, or synthetic fibers, providing both warmth and a luxurious tactile experience. Individuals choose fluffy yarns based on the specific texture and effect desired for their knitting or crocheting projects.