The evolution of the `C_(4)` photosynthetic system is probably one of the strategies for maximising the availability of (A)____ while minimising (B)____ loss

Answer

To solve the question regarding the evolution of the C4 photosynthetic system, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding C4 Photosynthesis**:
- C4 photosynthesis is a specialized mechanism used by certain plants to efficiently capture carbon dioxide (CO2) and minimize water loss. This system is particularly advantageous in hot and dry environments.

2. **Identifying the Key Components**:
- In C4 plants, photosynthesis occurs in two types of cells: mesophyll cells and bundle sheath cells. The mesophyll cells initially capture CO2 and convert it into a four-carbon compound (hence the name C4).

3. **Maximizing CO2 Availability**:
- One of the primary advantages of the C4 pathway is that it increases the concentration of CO2 at the site of the enzyme ribulose bisphosphate carboxylase/oxygenase (rubisco). This helps to maximize the availability of CO2 for the photosynthetic process.

4. **Minimizing Water Loss**:
- C4 plants are adapted to minimize water loss through a process called photorespiration, which is less prevalent in these plants compared to C3 plants. The structure of the bundle sheath cells helps to retain water and reduce transpiration.

5. **Finalizing the Answers**:
- Based on the understanding of the C4 photosynthetic system, we can conclude that the evolution of this system is aimed at maximizing the availability of **carbon dioxide (A)** while minimizing **water (B)** loss.

### Final Answer:
The evolution of the C4 photosynthetic system is probably one of the strategies for maximizing the availability of **(A) carbon dioxide** while minimizing **(B) water** loss.

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