Ecotone is a zone of transition between two different ecosystems. It is an area where two different plant communities meet and interact. Ecotones are characterized by a mixture of species from both ecosystems, and they often have unique ecological properties that are different from the adjacent ecosystems. Ecotones are important for biodiversity, as they support a variety of species that are not found in either of the adjacent ecosystems.

Characteristics of Ecotones:

- Ecotones are zones of transition between two different ecosystems.
- Ecotones are characterized by a mixture of species from both ecosystems.
- Ecotones often have unique ecological properties that are different from the adjacent ecosystems.
- Ecotones are important for biodiversity, as they support a variety of species that are not found in either of the adjacent ecosystems.

Ecotones can occur between different types of ecosystems such as forest and grassland, forest and wetland, or ocean and shore. The characteristics of an ecotone depend on the characteristics of the two adjacent ecosystems. For example, an ecotone between a forest and a grassland may have a mixture of trees and grasses, while an ecotone between a forest and a wetland may have a mixture of trees and aquatic plants.

In conclusion, an ecotone is a zone of transition between two different ecosystems characterized by a mixture of species from both ecosystems. Ecotones are important for biodiversity and have unique ecological properties that are different from the adjacent ecosystems.

An Ecotone describes an area that acts as a transition or boundary between two ecosystems. So, option B is correct.