Question 7
Why can aquatic animals survive in a body of water that is freezing over?
The right answer is the one marked above.
The density of water is greater than the density of ice. So when water turns to ice, the ice rises to the surface layers — and the water underneath stays liquid.
That liquid layer below the ice is a habitat. Water's oddness here is doing something no other property could: most substances are denser as solids and would sink, freezing a lake from the bottom up.