During mr. nye's science class, students were expected to identify various substances using physical properties they could easily measure. mr. nye gave each of the five groups a green, metal cube. the students had to identify what metal the cube was made of. the length of each side was 3.0 cm and the mass was 270 grams.

Given the length of each side of a cube and its mass, the density can be obtained which can then help identify the type of material it's made of. This is because density is a unique and intrinsic property of materials. For this problem, the density is determined to be 10g/cm^3. Looking at a table of densities, the metal is most likely actinium, which has an exact density of 10 g/cm^3.

The correct answer is d