Ice has a temperature colder than the temperature of water. Ice absorbs sunlight that is reflected by water. Ice traps more pollution than is trapped by water. Ice had a density lower than the density of water.
I gave my students this multiple choice question: Ice will form on small ponds when the temperature drops below 0°C. Which property of ice is most beneficial to fish living in these ponds?

Only one answer is correct among these 4 choices:
- Ice has a temperature colder than the temperature of water.
- Ice absorbs sunlight that is reflected by water.
- Ice traps more pollution than is trapped by water.
- Ice had a density lower than the density of water.

Could you tell me which one is correct?

Ice had a density lower than the density of water.