- High humus content causes the soil to be brown
- Humus is a source of nutrients in soil
- So, soil with high nutrients content will be brown

- Soil with high nutrients content will be brown
- Color of the soil can be used to indicate the soil component
- Hence, brown color can be used to indicate the soil is high in nutrients

So, brown color can be used to indicate the soil is high in nutrients
Question
Which property best indicates that soil contains nutrients?

Context
- High humus content causes the soil to be brown 
- Humus is a source of nutrients in soil 
- Color of the soil can be used to indicate the soil component