Which of the following statements best explains why soil is a renewable resource?
a.
wind and water cause soil erosion, which constantly replaces old soil with new soil.
b.
organic matter constantly replaces itself and provides nutrients for plants.
c.
deforestation provides a constant source of organic matter, which produces nutrients for plant growth.
d.
farmers constantly rotate their crops, preventing leaching and erosion.

B. Organic matter constantly replaces itself and provides nutrients for plants

Explanation:

The soil can be seen as a renewable resources because of one simple reason. That reason being that the nutrients that the soil gets from the organic matter are constantly replenished on their own, as there's always organic matter that decays.

Where ever there are plants and animals, the soil constantly gets organic matter (the amount depends on the climate type and location as well). The organic matter mostly affects the topsoil and provides nutrients for when when an animal or plant (or parts of the plant) die, so the microbes dispose them and the nutrients enrich the soil.

This organic matter base provides nutrients for growth of the plants, so it is a self relying system that functions perfectly well without any human intervention.