Use an argument about extent, supported with specific evidence. Identify the baseline, the change and a meaningful continuity; a cross-period reference helps only when the relationship is explained.
Original practice question, not an authentic AP item. Explain one way technological developments after 1900 affected human populations.
Worked response. “Medical innovations such as vaccines and antibiotics helped reduce deaths from infectious diseases. By improving survival, they contributed to longer average lives and could accelerate population growth where birth rates remained high.” This supplies a development and a mechanism. It claims neither universal access nor a guaranteed mark.
Extended practice. Assess the extent to which technology reduced the importance of geographic distance after 1900. Use communication and transportation evidence and one limit.
Possible argument. Radio, cellular communication and the internet reduced the barriers to sending information, while air travel and shipping containers supported movement over long distances. Yet access, borders and resource inequalities continued to shape participation. Technology changed how distance could be managed without making location irrelevant. To develop an essay, support these claims with specific historical examples and explain their relationships.