The response that best identifies how advances in science led to a longer life expectancy during the Industrial Revolution is:
"Once it was proven that germs cause disease, governments began to pass laws to improve sanitation in industrial cities."
This answer highlights the critical role that scientific advancements, particularly in the understanding of germ theory, played in public health improvements and consequently in increasing life expectancy. Enhanced sanitation and health measures arose from this knowledge, thus reducing disease transmission and improving overall health outcomes in industrial cities.