How can plants cause weathering?
A. Chemical reaction in plants change rocks and break them into smaller pieces
B. Plants need water, and water can weather rocks
C. Plants attract animals, and animals can burrow into rocks
D. Sprouting seeds and growing roots can cause rocks to break
D. Sprouting seeds and growing roots can cause rocks to break
D. Sprouting seeds and growing roots can cause rocks to break
To understand how plants can cause weathering, it helps to have a basic understanding of weathering itself. Weathering is the process of breaking down rocks into smaller pieces over time. There are two main types of weathering: mechanical weathering and chemical weathering.
Mechanical weathering is the physical breakdown of rocks into smaller fragments without any changes in their chemical composition. On the other hand, chemical weathering involves the chemical alteration of rocks due to exposure to various agents such as water, acids, and oxygen.
Now, let's look at how plants can contribute to weathering:
A. Chemical reaction in plants change rocks and break them into smaller pieces: While plants themselves do not undergo chemical reactions to break rocks, their roots and the organic acids they release can contribute to chemical weathering. Plant roots can grow into small cracks in rocks, exerting pressure and causing the cracks to expand. Additionally, some plants release weak organic acids which, over time, can chemically alter the composition of rocks and contribute to their breakdown.
B. Plants need water, and water can weather rocks: Plants require water for their survival. When plants absorb water from the soil through their roots, they can facilitate mechanical weathering. The water absorbed by plants can freeze and expand, exerting pressure on the rocks and causing them to break or crack. This process, known as frost wedging, is a type of mechanical weathering caused indirectly by plants.
D. Sprouting seeds and growing roots can cause rocks to break: As plants grow, their roots can exert pressure on rocks, causing them to crack or fragment. Seeds that sprout in crevices or cracks in rocks can also contribute to the physical breakdown of rocks as their roots grow and expand, putting pressure on the surrounding rock material.
Given these explanations, options A, B, and D all describe ways in which plants can cause weathering. Option C, on the other hand, is unrelated as it suggests that plants attracting animals, which can burrow into rocks, is responsible for weathering. Therefore, the correct answer is a combination of A, B, and D.