Final answer:
If water froze at its densest temperature, deeper areas of temperate-region lakes would freeze before the surface because this is where the densest water is found. Normally, water's unique property of maximum density occurring at 4 degrees Celsius (rather than at its freezing point) prevents this.
Step-by-step explanation:
In the case of temperate-region lakes, water is most dense at 4 degrees Celsius; however, it freezes at 0 degrees Celsius. This characteristic prevents deeper waters from freezing, allowing life to survive beneath a frozen surface layer. If water were to freeze at the same temperature at which it is densest, the entire lake would begin to freeze from the bottom up, starting with the deepest areas. Thus, deeper regions of temperate-region lakes would tend to freeze before the surface, which corresponds to option C.
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