Please Help, my problem is in this picture.

Name the element in group 17, period 2. (periodic table)

Need what is special about water as a compound? how does water regulate climate? what drives water evaporation?   why is the water vapor fresh water when it rises from the ocean? why might freshwater in the form of snow take longer to enter the water cycle again than liquid precipitation?   what is an aquifer? what role do people play in the water cycle? plz just answer as many as you can ! thx if you !

The independent variable in an experiment will be the variable that you o a) change ob) hold constant ng c) observe for changes