Correct Option: B. Implementing a rotational grazing system Detailed Explanation: Why Option B is Correct: 1. Definition of Rotational Grazing: Rotational grazing is a livestock management practice where animals are moved between different pastures or grazing areas. This allows for periods of rest for the grazed areas, enabling vegetation to recover and grow back.

1. Promoting Biodiversity:
2. Soil Health: Rotational grazing helps maintain soil health by preventing overgrazing. When animals graze continuously in one area, they can damage the vegetation and soil structure, leading to erosion and loss of nutrients. By rotating grazing areas, the soil can recover, promoting a diverse range of plant species.
3. Plant Diversity: Different plants have varying growth rates and resilience. Allowing certain areas to rest encourages a mix of grasses, legumes, and other plants to thrive, which supports a wider range of herbivores and, subsequently, predators and other wildlife.
4. Habitat Creation: Diverse plant life creates habitats for various organisms, including insects, birds, and mammals. This increases the overall biodiversity of the ecosystem.
5. Nutrient Cycling: Rotational grazing can enhance nutrient cycling. As animals graze, they also deposit manure, which can enrich the soil. When pastures are allowed to rest, the nutrients from the manure can be absorbed by the plants, creating a healthier ecosystem.
6. Resilience to Pests and Diseases: A diverse ecosystem is generally more resilient to pests and diseases. By promoting a variety of plant species, rotational grazing can reduce the likelihood of pest outbreaks that often occur in monocultures.

Why the Other Options are Incorrect: Option A: Monoculture planting of a single crop - Explanation: Monoculture involves planting a single crop over a large area. This practice can lead to reduced biodiversity because it creates a uniform environment that supports fewer species. It can also make crops more susceptible to pests and diseases, as they lack the natural checks and balances provided by a diverse ecosystem. Additionally, monocultures can deplete specific nutrients from the soil, leading to long-term degradation. Option C: Using chemical fertilizers and pesticides - Explanation: While chemical fertilizers can enhance crop yields, they often lead to soil degradation and water pollution. Pesticides can harm non-target species, including beneficial insects and other wildlife, thus reducing biodiversity. Over time, reliance on these chemicals can disrupt the natural balance of ecosystems, leading to a decline in species diversity. Option D: Deforestation to expand agricultural land - Explanation: Deforestation leads to habitat loss for countless species, resulting in a significant decline in biodiversity. It disrupts ecosystems and can lead to soil erosion, loss of carbon storage, and changes in local climate conditions. Expanding agricultural land through deforestation is detrimental to biodiversity and is not a sustainable practice. Summary of Key Points:

• Rotational grazing promotes soil health and plant diversity, which supports a wider range of wildlife.
• Monoculture reduces biodiversity and increases vulnerability to pests and diseases.
• Chemical fertilizers and pesticides can harm beneficial species and degrade ecosystems.
• Deforestation leads to habitat loss and significant declines in biodiversity.

By understanding these concepts, students can appreciate the importance of sustainable practices in promoting biodiversity within managed ecosystems.