Final answer:
The Industrial Revolution was the main factor in downplaying deaths in European society due to technological and scientific advancements that improved public health and food supplies.
Step-by-step explanation:
The phenomenon most influential in causing deaths to be downplayed in European society was The Industrial Revolution. This period was characterized by advances in science and technology which led to lower death rates thanks to improved knowledge about disease causes, better water supplies, sewers, and hygiene.
Additionally, the Industrial Revolution brought about better farming techniques and machines that increased food supply, as well as new sources of energy, like coal and electricity, which enhanced the efficiency of agricultural machines and transport systems for distributing food.