In the following objects, how many objects are stationary?
Tree, earth, sun, flying aeroplane, building, moving car

Explanation

To determine how many objects are stationary from the given list, we need to analyze each object based on whether it changes its position over time.

1. **Tree**: A tree is rooted in the ground and does not change its position. Therefore, it is stationary.

2. **Earth**: The Earth is constantly rotating on its axis and orbiting the Sun. Thus, it is not stationary.

3. **Sun**: The Sun appears to be stationary from our perspective on Earth, but it is actually moving through space. Therefore, it is not stationary.

4. **Flying aeroplane**: A flying aeroplane is in motion as it travels through the air. Thus, it is not stationary.

5. **Building**: A building is a fixed structure that does not change its position. Therefore, it is stationary.

6. **Moving car**: A moving car is in motion as it travels along a road. Thus, it is not stationary.

Now, let's summarize the stationary objects:
- Stationary Objects: Tree, Building
- Non-Stationary Objects: Earth, Sun, Flying aeroplane, Moving car

In total, there are **2 stationary objects** (Tree and Building).

### Final Answer:
There are **2 stationary objects** in the list.

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