Final answer:
Germany obstructed Cecil Rhodes's dream for British imperialism in Africa by establishing economic dominance, playing a role in the growth of militaries and naval arms race, and initiating guerrilla warfare during World War I.
Step-by-step explanation:
Germany obstructed Cecil Rhodes's dream for British imperialism in Africa by establishing economic dominance. They had established colonies in various regions of Africa, such as German East Africa, Togoland, and German Southwest Africa, which effectively blocked the proposed British expansion.
Additionally, Germany played a significant role in the growth of militaries and the naval arms race, leading to the formation of military alliances among Britain, France, and Russia to neutralize potential German territorial ambitions. This hindered British imperialism in Africa as they had to focus on European conflicts.
Lastly, during World War I, Germany lost its colonies in Africa, and the German commander in East Africa initiated guerrilla warfare tactics against the Allied troops, resulting in crop disruption and significant deaths.