Research questions that could have a big social impact, organised by discipline

Many of these questions are not well posed. For instance, the question, "What’s the average lifespan of the most common species of wild animals?", has a fairly simple answer. Most animals are insects, and most insect larva get eaten. Ergo, the average lifespan is probably measured in hours.

If the question is restricted to only mammals, then you still have fairly big ranges. Small animals may live only long enough to breed, while some larger animals (such as humans) may live for decades.

There are other questions about cultural longevity, well-being as well as broad and specific questions about risk factors. Communicating the desires behind these questions might be more helpful than the questions themselves.