How did the Glaciers from the last ice age affect the North American continent

In the figure, polygon abcd is transformed to create polygon a′b′c′d′. this transformation is a by a factor of .

What is an additional type of erosion found at the coast? what does it mean?

Read the article about the fraser river, one of the most important rivers in canada. what is the most important species of fish in this river? why are the numbers of these fish declining?