The correct answer is option 1: Peristalsis. Vegetables and fruits should be a part of our diet because they stimulate peristalsis. Peristalsis is the wave-like muscle contractions that occur in the digestive system, specifically in the esophagus, stomach, and intestines. These contractions help to push food through the digestive tract, aiding in the digestion and absorption of nutrients. When we consume vegetables and fruits, which are high in fiber, they provide bulk to the stool, making it easier for peristalsis to occur and promoting healthy bowel movements. This helps to prevent constipation and maintain regularity. Therefore, including vegetables and fruits in our diet is important for proper digestion and overall gastrointestinal health.