Bacteria grew in the ice cream. Heat was added to the ice cream. Water evaporated from the ice cream. Frozen berries were sprinkled on the ice cream.
I gave my students this multiple choice question: Ice cream in a bowl changed from solid to liquid in a few minutes. Which of the following most likely caused this change?

Only one answer is correct among these 4 choices:
- Bacteria grew in the ice cream.
- Heat was added to the ice cream.
- Water evaporated from the ice cream.
- Frozen berries were sprinkled on the ice cream.

Could you tell me which one is correct?

Heat was added to the ice cream.