The correct answer is option 2: Earthworm. Earthworms are often referred to as the farmer`s friend because they play an important role in improving soil fertility and health. They burrow through the soil, creating channels that help with aeration and water drainage. This improves the overall structure of the soil, making it easier for the roots of plants to grow and access nutrients. Additionally, earthworms digest organic matter such as dead plant material and animal waste, breaking it down into nutrient-rich castings that act as natural fertilizers. These castings further enrich the soil, providing essential nutrients for plant growth. Overall, the presence of earthworms in agricultural fields is beneficial and helps improve crop productivity.