Which best describes how soil is formed?
Soil is formed over a few days as wind blows particles of sand from one place to another.
Soil is formed over millions of years as rocks stack on top of each other.
Soil is formed over hundreds of years as rocks are broken down into tiny particles.
Soil is formed over millions of years as rocks are melted from extreme heat.
Soil is formed over hundreds of years as rocks are broken down into tiny particles.
Why are metal ores not found in every part of the world?
Metal ores are only found where there are mountains.
Only some places have the correct conditions for metal ores to form.
Only some places have the right water and wind to create metal ores.
Metal ores are only found where organisms have died.
Only some places have the correct conditions for metal ores to form.
The best description of how soil is formed is the third option: "Soil is formed over hundreds of years as rocks are broken down into tiny particles."
To understand how soil is formed, let's break down the process step by step:
1. Weathering: Over time, rocks on the Earth's surface are exposed to physical, chemical, and biological weathering processes. These processes include things like wind, water, ice, temperature changes, plant roots, and even microorganisms. These factors gradually break down the rocks into smaller fragments.
2. Erosion and Transport: Once rocks have been weathered, they can be eroded and transported by natural agents like wind, water, ice, and gravity. For example, wind can carry tiny particles of rock such as sand and silt over long distances. Similarly, water can transport sediments downstream in rivers and streams.
3. Deposition: As the eroded particles are transported, they eventually come to rest and settle. This is known as deposition. The particles settle in layers, building up over time.
4. Organic Matter: As the deposition of sediments occurs, organic matter from plants, animals, and microorganisms can accumulate on the surface. This organic material, such as decomposed plant and animal remains, contributes to the development of soil fertility.
5. Biological Activity: Various organisms, including bacteria, fungi, worms, insects, and plant roots, play a crucial role in soil formation. These organisms break down organic matter and release nutrients, contributing to the overall structure and fertility of the soil.
Over hundreds of years, the gradual breakdown of rocks, along with the accumulation of organic matter and the influence of biological activity, results in the formation of soil. Therefore, the third option accurately describes the process of how soil is formed.