Wht does the term green revolution refer to?

The term Green Revolution refer as the revolution or huge increment in the global agriculture with the help of advance techniques, high yielding variety of seeds, better use of pesticides.

In United States, the green revolution started in 1940’s. The seed breeding technologies of Europe and United States were used in 1930s to produce high yielding variety of seeds which were best suited to the climatic and soil conditions in 1940s. The credit of this revolution goes to Norman Borlaug who received Nobel Peace Prize in 1970.

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.