Answer
a) Darker
b) Lighter
c) We cannot determine
Work Step by Step
a) The darker block is smaller and heavier, therefore, it must be more dense.
b) Both blocks are of the same size and lighter-colored is heavier, therefore, it must be more dense.
c) The darker block is both greater in size and heavier, therefore, we cannot determine their relative densities. Its position on the scale could be due to its volume or density.
