Mouldy bread: A science experiment
I just bought a loaf of fresh-baked bread (without preservatives!) from the bakery. I placed a slice of bread in a ziploc bag, and left it out on the kitchen counter. I placed a second slice of bread in a separate ziploc bag and placed it in the refrigerator. I placed a third slice of bread in a different ziploc bag and placed it in the freezer. I left the slices of bread in each of the three places for 2 weeks. I observed the slices of bread for mould growth every other day.
What is the only factor that was changed in the experiment?

Explanation

**Step-by-Step Solution:**

1. **Identify the Experiment Setup**: The experiment involves three slices of bread placed in different environments: one at room temperature on the kitchen counter, one in the refrigerator, and one in the freezer.

2. **Understand the Purpose of the Experiment**: The goal is to observe mold growth on the bread slices over a period of two weeks.

3. **Analyze the Conditions**:
- The first slice is kept at room temperature, which is ideal for mold growth.
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