What is loam characterized by?

Loam is best characterized as a mixture of sand, silt, and clay particles, typically in a relatively balanced ratio that results in a soil type favorable for plant growth. The inclusion of sand provides good drainage and aeration, while clay helps retain moisture and nutrients. This combination makes loam ideal for cultivating various plants, as it has excellent fertility and physical properties. The balance between the different particle sizes allows loam to hold enough water and nutrients for plants, yet still allows for adequate drainage, preventing waterlogging.

The other options do not accurately encapsulate what loam is or its beneficial characteristics. A mixture of organic matter and minerals is related to compost or organic-rich soil, while a layer of compacted soil refers to soil that has been compressed and lacks porosity, which is detrimental to plant growth. A single type of soil particle would not be representative of loam but rather a uniform soil type, lacking the beneficial properties derived from a mixture.