Which mineral is never found freely in nature but is extracted from a chemical compound? a. coal b. salt c. gold d. silicon

D. Silicon

Explanation:

Silicon is very abundant in nature, in the entire universe it is the 7th most abundant, behind the following elements: hydrogen, helium, neon, oxygen, nitrogen and carbon. In the Earth's crust, it is the second largest (27.7%), second only to oxygen.

However, it is never found naturally in isolation, it is always combined with some other element, or chemical compound. For this reason, it was first prepared in the laboratory, in 1824, by the Swedish chemist Jöns Jacob Berzelius, by heating silicon tetrafluoride with potassium.

it would lead to upper respiratory infections and pneumonia.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.