______ are generally moved by a mass or bulk flow system.

Options

A. Water and minerals
B. Water and organic molecule
C. Water, minerals and food
D. Only water

Answer

To answer the question "______ are generally moved by a mass or bulk flow system," we need to analyze the options provided and understand the concept of mass or bulk flow in plants.

### Step-by-Step Solution:

1. **Understanding Mass or Bulk Flow**:
- Mass flow or bulk flow refers to the movement of substances in large quantities, typically driven by pressure differences. In plants, this is primarily observed in the transport systems of xylem and phloem.

2. **Identifying the Substances Moved**:
- In plants, the xylem is responsible for transporting water and minerals from the roots to the leaves, while the phloem transports organic molecules (mainly sugars) from the leaves (source) to other parts of the plant (sink).

3. **Analyzing the Options**:
- **Option 1: Water and minerals**: This is partially correct as water and minerals are transported via xylem, but it does not encompass the transport of organic molecules.
- **Option 2: Water and organic molecules**: This option is also partially correct but lacks the mention of minerals.
- **Option 3: Water, minerals, and food**: This option is the most comprehensive as it includes all three components transported in plants: water, minerals, and organic molecules (food).
- **Option 4: Only water**: This option is incorrect as it does not account for the other substances.

4. **Conclusion**:
- The correct answer is **"water, minerals, and food"** as these are the components that are generally moved by a mass or bulk flow system in plants.

### Final Answer:
**Water, minerals, and food** are generally moved by a mass or bulk flow system.

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