Answer:
1. An exclave is a part of a country not connected to its main territory
2. Mulch is a protective covering put over soil to prevent evaporation or erosion
3. Peat is decomposed organic material that can be used for fuel and mulch peat .
4. Permafrost is a permanently frozen soil beneath the surface in polar and near-polar areas.
5. A waterway is un-navigable if it is unable to be used for travel by water .