Friction between a skateboard wheel and the surface produces ?

What is the answer for the complicated molecules that make up living things usually contain carbon. why is carbon so important in these molecules?

What materials must dams have to produce electricity, and what must occur?

First described the system of fingerprint ridges and spirals, which eventually were used for fingerprinting. a.) fare and fidelis’s pathology b.) dr. calvin goddard c.) hans gross d.) marcelo malpighi e.) leeuvenhoek’s microscope