Concentration of water molecules in a system determines

Options

A. Uphill transport rate
B. Number of carrier proteins
C. Water potential of the system
D. Membrane permeability

Answer

To answer the question "Concentration of water molecules in a system determines," we will analyze the options provided and determine which one is correct based on the principles of plant biology.

### Step-by-Step Solution:

1. **Understanding Concentration of Water Molecules**:
- The concentration of water molecules refers to the amount of water present in a given system. It is a crucial factor in determining various physiological processes in plants.

2. **Analyzing the Options**:
- **Uphill Transport Rate**: This refers to the transport of substances against their concentration gradient, which typically requires energy. The concentration of water molecules does not directly influence this process. Therefore, this option is incorrect.

- **Number of Carrier Proteins**: Carrier proteins facilitate the transport of molecules across cell membranes. The number of these proteins is generally fixed and does not change with the concentration of water. Thus, this option is also incorrect.

- **Water Potential of the System**: Water potential is defined as the potential energy of water in a system and is influenced by the concentration of water molecules. Higher concentrations of water lead to higher water potential, making this option correct.

- **Membrane Permeability**: This refers to how easily substances can pass through a membrane. While membrane permeability is important for transport, it is primarily determined by the structure of the membrane itself and does not change with the concentration of water. Therefore, this option is incorrect.

3. **Conclusion**:
- The correct answer is that the concentration of water molecules in a system determines the **water potential of the system**.

### Final Answer:
The concentration of water molecules in a system determines the water potential of the system.

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