Final answer:
The bulk-forming laxative in the options provided is A) Psyllium. It works by absorbing water and forming a bulkier, softer stool. Other options listed are different types of laxatives or compounds not used as laxatives.
Step-by-step explanation:
A bulk-forming laxative refers to a type of laxative that works by absorbing water in the intestines to form a softer, bulkier stool that is easier to pass. The correct answer to the question is A) Psyllium. Psyllium is a form of fiber made from the husks of the Plantago ovata plant's seeds. It is known as a viscous fiber that can thicken the fecal mass and stimulate peristalsis in the digestive tract. Docusate sodium, classified as B), is a stool softener, which makes the stool softer and easier to pass by increasing the amount of water the stool absorbs in the gut. Bisacodyl, referred to as C), is a stimulant laxative that speeds up the movements of the intestinal muscles to facilitate bowel movements. Polyethylene, mentioned in D), is not a laxative but a common plastic material used in products such as beach balls and hard plastic bottles.
Good sources of insoluble fiber include whole wheat, wheat bran, beans, and potatoes. Insoluble fiber does not dissolve in water and is inert to digestive enzymes in the upper gastrointestinal tract, providing bulking, absorbing water as it moves through the digestive system, and easing defecation. The stretch reflex is a physiological response where the presence of fecal matter or bulk stimulates the walls of the large intestine, leading to a bowel movement.