Final answer:
Soil contains humus, sand, and clay, each contributing to soil structure, nutrient availability, and water retention.
Step-by-step explanation:
Three particles or objects that are commonly found in soil include humus, sand, and clay. Humus is the organic material that significantly affects soil structure, is made up of microorganisms both dead and alive, dead animals and plants in various stages of decay, and provides important nutrients and water to plants. Sand particles, which are inorganic and have a diameter of 0.1 to 2 mm, contribute to soil drainage and aeration. Clay is made up of very fine particles with a diameter of less than 0.002 mm, is rich in minerals like feldspar and silica, and is known for its ability to retain water and nutrients.