Why is charcoal a limited drawing medium

option c (nickel) is not found in earth's crust. the earth's crust basically contains eight (8) elements namely: oxygen, silicon, aluminum, iron, calcium, sodium, potassium and magnesium (listed in order of abundance).

the above mentioned statements talks about the creativity of an artist and to what extend they can utilize and experiment on the objects provided.   differing size and subjects are given so that an image of wisdom is created. displaying a transition from light to dark in something by darkening sections in order to create a shadow. and lastly, putting bits and pieces together to formulate a new image.