Evolution through natural selection will occur most rapidly for populations of plants that:

• A. Are already well adapted to the environment.
• B. Reproduce sexually and live in an unstable environment.
• C. Live in an unchanging environment.
• D. Are in the same genus.

Answer: (B)

Verified step by step guidance

1. Understand the concept of natural selection: Natural selection is a process where organisms better adapted to their environment tend to survive and produce more offspring. It is a key mechanism of evolution.
2. Consider the role of sexual reproduction: Sexual reproduction increases genetic diversity within a population. This diversity provides a wider range of traits that can be selected for or against by environmental pressures.
3. Analyze the impact of environmental stability: In an unstable environment, conditions change frequently, which can create new challenges for survival. Populations in such environments may evolve more rapidly as they adapt to these changes.
4. Evaluate the adaptation level: Populations that are already well adapted to their environment may experience slower evolutionary change because there is less pressure to adapt further.
5. Consider the genetic relationship: Being in the same genus does not necessarily affect the rate of evolution through natural selection. The key factors are genetic diversity and environmental pressures.