Final answer:
The exact number of soldiers each alliance lost during the 7-day Battle of the Marne isn't detailed in the provided reference, but the battle was one of many during WWI with severe casualties on both sides, notably marking the start of trench warfare.
Step-by-step explanation:
Battle of the Marne Casualties
The Battle of the Marne was a significant confrontation during World War I where British and French forces halted the German offensive between September 6th and September 12th, 1914. Both alliances suffered heavy casualties during this battle, which was one of the first instances of trench warfare on the Western Front. Unfortunately, specific casualty figures for this particular battle are not provided in the reference material; however, we can see from other major battles such as Verdun, the Somme, and the Brusilov Offensive the high cost in human lives. The Battle of the Somme, for instance, resulted in over a million casualties, with 60,000 British soldiers killed or wounded on the first day alone.
It is important to note that the Battle of the Marne marked a turning point in WWI, transitioning into a war of attrition where both sides experienced severe losses without gaining significant ground. This battle, with its mass deployments and development of trench warfare, set the stage for the brutality and stalemate that would characterize much of the conflict. The exact number of losses in the 7-day Battle of the Marne is not detailed here, but it was undoubtedly high, contributing to the devastating toll of World War I.