Question

1.3 sustaining terrestrial ecosystems

in which layer are mineral deposits, such as iron and phosphorus, found?

topsoil
subsoil
bedrock

Explanation:

Identify the question

The question asks to identify the soil layer where mineral deposits, such as iron and phosphorus, are primarily found.

Analyze the soil layers

Soil is divided into distinct horizontal layers called horizons:

• Topsoil (A Horizon): Rich in organic matter (humus) and vital for plant growth, but minerals are often leached downward from this layer.
• Subsoil (B Horizon): Accumulates leached minerals, clay, and metal salts (like iron, aluminum, and phosphorus) from the upper layers.
• Bedrock (R Horizon): The solid rock layer beneath the soil that has not yet weathered.

Determine the correct layer

Since minerals leach downward from the topsoil and accumulate in the layer directly beneath it, the subsoil is the primary layer where these mineral deposits are concentrated.

Answer:

• Topsoil
• Subsoil (Correct answer)
• Bedrock