Why did a drop of water need to be added in order to initiate the reaction?
select one:
a. because the water is needed to wet the chlorine gas so the reaction could occur
b. because the water is needed to cool off the reaction so the flask will not explode
c. because the water is needed to remove a coating on the surface of the metal
d. because the water is needed to wet the sand and keep the reaction safe

Although respiratory organs vary across different organisms, they all contain respiratory surfaces that have a large surface area and are extremely thin. explain why having an extremely thin respiratory surface with a large surface area is advantageous for the process of gas exchange

What is the percentage of hydrogen in c2h4

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 !