Water is a polar molecule. Water has a high surface tension. Water can change from a solid directly to a gas. Water is less dense as a solid than as a liquid.
Which property of water is essential for organisms to survive in freshwater ponds during the winter months?

Options:
- Water is a polar molecule.
- Water has a high surface tension.
- Water can change from a solid directly to a gas.
- Water is less dense as a solid than as a liquid.

Water is less dense as a solid than as a liquid.