The word that is different from the rest is B: Tower. Here's a detailed explanation:
1. Sea:
- A sea is a large body of saltwater that is partially enclosed by land.
- It is a natural feature that covers a significant portion of the Earth's surface.
- Seas are known for their vastness, biodiversity, and the presence of marine life.
2. Tower:
- A tower is a tall structure that is typically taller than its diameter.
- It is usually built for various purposes such as communication, observation, or as a part of a building.
- Towers can be found in cities, historic sites, and landmarks.
3. Mountain:
- A mountain is a large landform that rises above the surrounding land in a limited area.
- It is typically steeper and taller than a hill.
- Mountains are formed through tectonic processes and are characterized by their peaks and rugged terrain.
4. River:
- A river is a natural flowing watercourse that usually originates from mountains, hills, or other sources.
- It flows towards an ocean, sea, lake, or another river, forming a channel along its course.
- Rivers are vital for various ecosystems and provide habitats for a diverse range of plants and animals.
In summary, the word "Tower" is different from the rest as it does not represent a natural geographic feature like the others (Sea, Mountain, and River). It is a man-made structure that serves different purposes.