What is the valency of Aluminium and nitrate in Al(NO3)3 ?​

What layer of the atmosphere is directly above the troposphere?

Ais a mountain created from eruptions of lava, ash, rocks, and hot gases.

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!