The correct option is LOESS.
Loess refers to a compacted yellowish deposit of wind blown sediments which is usually found extensively in the mid latitudes. Loess is formed by the accumulation of dust that had been blown by the wind. Scientists believed that about 10% of the earth's land area is covered by loess.<span />
The answer is true it can be traced to one particular reason.
There are three meanings.
1. the process or fact of isolating or being isolated.
2. denoting a hospital or ward for patients with contagious or infectious diseases.
3. an instance of isolating something, especially a compound or microorganism.
