* Wilderness: This is an abstract concept, representing a natural area untouched by human civilization.
* Culture: This is also an abstract concept, representing the customs, arts, social institutions, and achievements of a particular nation, people, or group.
The other words are concrete nouns:
* Leather: This is a tangible material.
* Culture: This is an abstract concept, representing the customs, arts, social institutions, and achievements of a particular nation, people, or group.
Let me know if you have any other questions!