Why does air pressure decrease as altitude increases?

Which is the most reasonable capacity of a water pitcher. m a 2 ml b 20 ml c 2 l d 20 l

Plz answer ! find the alps. what countries and country borders intersect this major mountain range? which borders seem to be defined by the edges of the mountains? which borders seem to be defined by the edges of the mountains? which borders cut across the mountains?

Ineed , i need to create a power point in life science here is a picture explaining a little what the topic is about, me with some information for my slides : (