the color of the sample the mass of the sample the amount of clay in the sample the amount of rock in the sample
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Humus is an organic material that makes up soil. Which characteristic best indicates that soil has a high humus content?
Possibilities:
- the color of the sample
- the mass of the sample
- the amount of clay in the sample
- the amount of rock in the sample

the color of the sample