If a=(-1,-3) and b=(11,-8), what is the length of ab

Number the steps from when a stimulus is received to when the body reacts

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?

What does the plate tectonic theroy describe?