Why were armies positions moved so little during WWl

neither army could advance its position, mainly because war was being waged in a very different way than it had been during the 19th century. Forward-moving strategies such as head-on infantry attacks were no longer effective or feasible against modern weaponry such as machine guns and heavy artillery.

Explanation:

the correct answer is “opportunity cost”. opportunity cost is what a company misses out because it decided in one option over another one. in this case, the company decided to invest in building a factory so it gave up another possible benefit or profit in order to achieve success with the factory.  

trade-off is not the correct answer since it is a situation in which you accept losing something in return for benefits in other areas.

and finally, consequence is a general term used to accept what it comes when you make a decision. it can be a positive or negative consequence depending if the decision you took was the correct one.