To determine the correct order of the digestive process from the given steps, we need to understand the sequence of events that occur as food travels through the human digestive system. Here’s the step-by-step breakdown:
1. **Step 1: Food is moistened, breakdown of starch begins.**
- This step occurs in the mouth where saliva moistens the food and contains enzymes that start breaking down starch (a carbohydrate).
2. **Step 2: Food is liquefied, breakdown of proteins begins.**
- After the mouth, the food travels down the esophagus to the stomach. In the stomach, the food is mixed with gastric juices, which liquefy it and begin the digestion of proteins.
3. **Step 3: Proteins, carbohydrates, and fats break down, nutrients are absorbed into the bloodstream.**
- The partially digested food then moves to the small intestine, where the majority of digestion occurs. Here, enzymes continue to break down proteins, carbohydrates, and fats, and the nutrients are absorbed into the bloodstream.
4. **Step 4: Water and vitamin absorption begins.**
- Finally, the remaining undigested food moves to the large intestine, where water and vitamins are absorbed.
Putting these steps in the correct order, we have:
1. (i) Food is moistened, breakdown of starch begins.
2. (iii) Food is liquefied, breakdown of proteins begins.
3. (ii) Proteins, carbohydrates, and fats break down, nutrients are absorbed into the bloodstream.
4. (iv) Water and vitamin absorption begins.
Thus, the correct order is: (i), (iii), (ii), (iv).
