500
Which of these statements gives an accurate description of the composition of soil?
a) Soil contains 50% organic material, 20% minerals, 10% air, and 10% water.
b) Soil contains 45% minerals, 25% air, 25% water, and 5% organic material.
c) Soil contains 20% minerals, 15% air, 15% water, and 50% organic material.
d) Soil contains 45% air, 50% water, and 5% organic material.
b) Soil contains 45% minerals, 25% air, 25% water, and 5% organic material.