Question

life expectancy in the us
which factor best explains why the graph changes from 1990 to 2010?
new technology protects soldiers from risky reconnaissance missions.
new technology allows farmers to grow genetically modified crops.
new technology allows us to find and use new energy sources.
new technology has improved medical imaging and surgery.

Explanation:

The graph shows life - expectancy in the US. Medical advancements like improved imaging and surgery directly contribute to increased life - expectancy. Other options are not related to life - expectancy.

Answer:

New technology has improved medical imaging and surgery.