What is the primary characteristic on which the broad division of organisms is made?

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the primary characteristic used for the broad division of organisms.

2. **Identifying the Primary Characteristic**: The primary characteristic for classifying living organisms is the "nature of the cell."

3. **Defining the Nature of the Cell**: The nature of the cell refers to whether the cells have membrane-bound organelles and a well-defined nucleus.

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