1: They had toxic metals and they were massive. They took up way too much space for some people's money and they weren't exactly the best and most efficient so some people didn't like them.
3: Solar panels would work very well in space because they don't have clouds and dust to block out sunlight like there is on Earth. In space, there wouldn't be a source such as wind or coal or anything, so it would be more efficient to use solar panels since there is a more direct sunlight path.
Low humidity is typically associated with cold temperatures since cold air holds less water compared to warm air. While it is possible for indoor humidity to be as low as 10%, most people generally find humidity levels of about 40 to 45 percent comfortable.
