Pls help ASAP I think its six so can someone tell me if I am right or whats the correct answer to the picture

Astring vibrates with a frequency of 10 hz. why can't a person hear the sound waves produced by the vibrating string, no matter how large the amplitude of the waves? out! this is homework and due tomorrow! you so much!

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 !

An unknown substance was put in a container. the substance filled up the container from bottom up, taking half of the space in the container. what is most likely the state of matter of the substance? gas liquid plasma solid