Biochemical limestone is when the calcium carbonate is locked into the fossil shells and skeletons of marine organisms.
But chemical limestone is when the calcium carbonate is in the form of calcite mineral crystals.
Hope it helps!
I have no idea, but I wouldn't use Wikipedia.. The "facts" on there aren't always true. That's why we aren't allowed to use it in my high school.
I think that the beginning of the question says "ill health"
Yes, this is true. low earnings are often correlated with bad health - it's because poor people have less access to health care, less access to healthy food and might be forced to do jobs which are stressful and demanding.