Final answer:
Mechanical and chemical weathering often act together, with mechanical processes breaking rocks physically and chemical processes altering rock minerals, which is true. Water acts as a common agent in both, promoting weathering and influencing soil formation.
Step-by-step explanation:
The statement Mechanical and chemical weathering usually act in concert with one another is true. These two forms of weathering often work together to break down rocks and contribute to soil formation. While mechanical weathering is responsible for physically breaking down rock into smaller pieces through processes like freeze-thaw and exfoliation, chemical weathering involves the alteration of rock minerals by chemical reactions, often with water as an agent, leading to products like clay minerals or dissolved ions.
For example, the presence of water can accelerate mechanical weathering by processes such as ice wedging, where water seeps into cracks, freezes, expands, and widens the cracks. Concurrently, water also facilitates chemical weathering by dissolving and reacting with minerals in the rock, altering their composition. Therefore, these processes significantly overlap and contribute to the continued breakdown of rock material into sediment, influencing soil characteristics and the soil-building process.