Final answer:
Earthworms create healthier soil by eating soil and extracting organic matter, which they excrete as nutrient-rich worm casts. Their burrowing activities also help to aerate the soil.
Step-by-step explanation:
Earthworms create healthier soil through their feeding and burrowing activities. They eat soil and extract organic matter from it, which they then excrete as nutrient-rich worm casts. These worm casts contribute to the health of the soil by improving its fertility. Additionally, the burrowing activities of earthworms help to aerate the soil, allowing for better circulation of air and water, which benefits plant growth.