Q: Fact 1: Adding salt to a solid decreases the freezing point of that solid. Fact 2: Ice is the solid form of water. Given the two facts above, what decreases the freezing point of ice?

Possible answers:
1). hyperthyroidism;
2). increasing temperature;
3). heating liquids;
4). lowering temperature;
5). Dehydration;
6). keeping the temperature steady;
7). adding salt;
8). hypothyroidism;
A:
7).