How does altitude affect air pressure?

Can someone ! who is the intended audience for cortés—general description of tenochtitlán i need to fill out a hap-p chart pleaaasse

Why are radio observatories located in valleys far away from urban centers? a. to shield them from electromagnetic interference b. to avoid sound pollution c. to avoid disturbing people living in the city d. to shield them from water vapor

What property does soil or rock need to be permeable? a.)young b.)old c.)non porous d.)porosity