President Calvin Coolidge approach the American economy can be best described as

the difference is that white collar worker performs skills like worker as a scientist or well blue collars do physical work and they do services like being a cook.

offline recommendation systems option b

because recommendation systems produce a list of two ways

1. through collaborative filtering

or

2. through content-based filtering

answer; andrew jackson approved nullification by signing it into law,and john calhoun opposed it saying it was unconstitutional;

the graph shows the spread of railways in the 1800s.

based on the graph, the conclusion that can be drawn about germany is answer d)   by 1880, germany had more rail lines than great britain and russia.