7 and 6 were apart of it, also 4
Answer:
Sierra Nevada, also called Sierra Nevadas
There were many ways in which the development of trench warfare influenced World War I. One of the most important were the health problems that trenches caused on soldiers. Apart from that, another characteristic of the trenches warfare was that it conducted the battles really close. Trenches made armies re-think about the strategies they were using in order not to commit the same mistakes again.
