Inner core
The inner core is the most dense layer of earth. The second next dense layer would be the outer core.
A nebula is an interstellar cloud of "Dust and Gas"
You might put harmful toxins in the beach or into the ocean which would kill wildlife
I believe it’s Precambrian.
The answer that best fits the description above is the hormone GLUCOCORTICOID. This was according to Hans Selye, an Austrian-Canadian endocrinologist. According to him, ill health induced by exposure of chronic stress is due to the secretion of the hormone glucocorticoid.