Correct Option: B. Selective logging and thinning Detailed Explanation Why Option B is Correct: Selective logging and thinning are practices that involve the careful removal of certain trees while leaving others intact. This method is designed to maintain the overall structure and biodiversity of the forest ecosystem. Here’s why this practice is effective for maintaining biodiversity:

1. Preservation of Habitat: By selectively removing trees, the habitat for various species is preserved. Many organisms depend on specific tree species for food, shelter, and breeding. This practice helps maintain a diverse range of habitats within the forest.
2. Encouragement of Growth: Thinning allows more light to reach the forest floor, promoting the growth of understory plants and younger trees. This increased plant diversity supports a wider range of animal species, from insects to larger mammals.
3. Sustainable Yield: Selective logging can be done sustainably, meaning that it can provide timber and other forest products without depleting the forest's resources. This balance is crucial for long-term biodiversity.
4. Reduced Soil Erosion: By maintaining tree cover, selective logging helps prevent soil erosion, which can be detrimental to the ecosystem. Healthy soil supports diverse plant life, which in turn supports a variety of animal species.

Why the Other Options are Wrong or Weaker: A. Clear-cutting of large areas - Explanation: Clear-cutting involves removing all trees in a designated area, which drastically alters the ecosystem. This practice leads to habitat destruction, loss of biodiversity, and soil degradation. While it may be economically beneficial in the short term, it is detrimental to the long-term health of the forest and its inhabitants. C. Planting monocultures of fast-growing species - Explanation: Monocultures involve planting a single species over a large area. This practice reduces genetic diversity and makes the ecosystem more vulnerable to pests and diseases. It also fails to support the variety of wildlife that a mixed-species forest would, as many species rely on a diverse range of plants for food and habitat. D. Frequent burning of underbrush - Explanation: While controlled burns can be beneficial for certain ecosystems by reducing fuel loads and promoting new growth, frequent burning can be harmful. It can lead to the loss of plant species that are not fire-adapted, disrupt animal habitats, and contribute to air pollution. This practice does not inherently support biodiversity and can be detrimental if not managed carefully. Summary of Key Points:

• Selective logging and thinning maintain habitat diversity and promote the growth of various plant species.
• Clear-cutting destroys habitats and reduces biodiversity significantly.
• Monocultures limit genetic diversity and increase vulnerability to pests and diseases.
• Frequent burning can disrupt ecosystems and harm species that are not adapted to fire.

By understanding these practices and their impacts, we can make informed decisions that support biodiversity in forest ecosystems during management activities.