Which state of water allows fish to remain in a lake when winter temperatures are below 0 degrees celcius

What does the word submerged mean in the following sentence? after it rained for three days in a row, the streets were completely submerged.

When the land and the see warm up at different rates during the day, what is generally the result? -a snow -b rain -c a breeze -d warm temperature

What is the best way to describes europe population