What force causes objects in space to be grouped together?

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the force that causes objects in space to be grouped together. This implies that we need to identify a specific force that has a significant effect on the arrangement of celestial bodies.

2. **Identifying the Force**: The force that causes objects in space to be grouped together is known as **gravity**.

3. **Defining Gravity**: Gravity is defined as an invisible force that attracts two bodies towards each other. This force is dependent on the mass of the objects and the distance between them.

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