Most people recognize biodiversity by species—a group of individual living organisms that can interbreed. Examples of species include blue whales, white-tailed deer, white pine trees, sunflowers, and microscopic bacteria that can't even be seen by the naked eye.
It turns out that many materials can be solid at a higher temperature if the pressure is also higher. so even though it is hotter in the inner core the pressure in the core is also higher and you can have a solid iron nickel instead of liquid
Group 18 non reactive and non metallic