Question

chemical bonds
coal, graphite, and diamond are made of carbon.
why are they so different?
depends on the # of bonds between the c - atoms.
graphite – 1, coal – 2, diamond – 4
multiple - choice question
coal, graphite and diamonds are all made up of what element?
helium
calcium
carbon

Explanation:

The text above the question states that coal, graphite, and diamond are made of carbon. Helium is a noble gas, and calcium is a different element, so the correct element is carbon.

Answer:

carbon (the option with "carbon" as the text, so the checkbox next to "carbon" should be selected)