Earthworm
earthworm: An invertebrate animal with a long thin body divided into many segments, living in large numbers in the soil. Earthworms aerate the soil as they tunnel. They also eat organic matter and help increase the soils fertility. They help stabilize the soil structure by compressing material and mixing it with organic matter and calcium. It is believed that they also secrete a hormone which encourages rooting by plants. Earthworms are beneficial for farmers as they enhance soil fertility and structure, promoting healthy crop growth.