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 technoigy 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 increasing from 1960 - 2010. Improvements in medical imaging and surgery due to new technology directly impact human health and lifespan, which is related to life - expectancy. The other options are about military, agriculture, and energy, which do not directly affect life - expectancy.

Answer:

New technology has improved medical imaging and surgery.