Which of the following causes of the Evil Quartet involves the combination loss of a coevolved plant-pollinator mutualism?

Options

A. farmentation
B. alien species invasion
C. over-exploitation
D. co-extinction

Answer

To solve the question regarding which cause of the Evil Quartet involves the combination loss of a coevolved plant-pollinator mutualism, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Evil Quartet**: The Evil Quartet refers to four main causes that lead to a decrease in species richness. These are:
- Fragmentation
- Alien species invasion
- Over-exploitation
- Co-extinction

2. **Define Co-evolved Plant-Pollinator Mutualism**: This mutualism is a relationship where plants provide nectar to pollinators, and in return, pollinators help in the fertilization process by transferring pollen between flowers. This relationship is crucial for the survival of both parties.

3. **Identify the Impact of Extinction**: If a pollinator species goes extinct, the plants that rely on that pollinator for reproduction may also face extinction due to their inability to reproduce effectively without the pollinator. This interdependence means that the loss of one species can lead to the loss of another.

4. **Connect to Co-extinction**: The term "co-extinction" specifically refers to the phenomenon where the extinction of one species leads to the extinction of another species that is dependent on it. In this case, the loss of a pollinator would directly affect the coevolved plant species, leading to their decline or extinction.

5. **Conclusion**: Therefore, the cause of the Evil Quartet that involves the combination loss of a coevolved plant-pollinator mutualism is **co-extinction**.

### Final Answer:
The correct answer is **co-extinction**.

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