GEOLOGY

Detailed explanation-1: -Named in 1789 by the German chemist and mineralogist A.G. Werner, the name for graphite is derived from the Greek Word graphein, which means: to write. The name therefore denotes the primary use of graphite as an ingredient used to make the lead for writing pencils.

Detailed explanation-2: -In the process, we learned that pencil lead (actually not lead at all but a mineral called graphite) has a storied past.

Detailed explanation-3: -Answer and Explanation: Pencil lead is made from graphite, which is a form of carbon mixed with varying quantities of clay. Graphite is a mineral.

Detailed explanation-4: -Therefore, graphite is used in pencils. It leaves a black trace of writing on paper because it consists of layers of carbon atoms that slide over each other, option (D) is correct.

Detailed explanation-5: -Because chemistry was a young science at the time, people thought graphite was a form of lead; hence the name given to pencils. The next step in the evolution of the pencil came in the late 1500s, when graphite rods were placed inside wood sleeves that were glued together. This made pencils easier to use.