The correct option is (c).
Explanation
Roughage, also known as dietary fiber, is an indigestible portion of food derived from plants. While it does not provide nutrients (like vitamins or minerals), it is an essential component of a healthy diet due to its mechanical role in the digestive system.
Statement-wise Analysis
- Statement 1 is Incorrect. Roughage is primarily obtained from plant products. Main sources include whole grains, pulses, potatoes, fresh fruits, and vegetables. Animal products such as milk, meat, and eggs do not contain dietary fiber.
- Statement 2 is Correct. The primary physiological function of roughage is to facilitate the movement of material through the digestive tract. It assists the body in expelling undigested food and waste, thereby preventing constipation.
- Statement 3 is Correct. Roughage absorbs water and adds bulk to the food. This increased volume stimulates the muscular contractions (peristalsis) of the intestines, ensuring the smooth passage of food through the alimentary canal.
Key Takeaway
Roughage (Dietary Fiber) is exclusively plant-based and provides no nutritional value, but is critical for maintaining digestive health by adding bulk to stool and aiding in waste elimination.