Final answer:
If the blue and yellow blocks sink, they are denser than water. The mass and density relationship determines whether a block will sink or float; a block of the same volume will have a different density if it has a different mass. In a simulation, a floating foam block's displacement can be used to calculate the mass of the displaced water using the known density of water.
Step-by-step explanation:
When placing all the blocks in the water, certain observations about their densities can be made. Blocks that sink are denser than water, while those that float are less dense. If the blue and yellow blocks sink, they are denser than water (A is correct). Without knowing the exact behavior of the green and red blocks, we can't confirm which is the least dense (B and C cannot be determined). Statement D about the masses of the blocks is unrelated to their behavior in water unless we have a measure of their volumes to consider alongside. Lastly, if the red block floats, it is less dense than water, but we cannot determine if it is the least dense without comparing it to the green block or knowing the green block's behavior (E cannot be determined).
Mass and density are two properties that can tell us how substances will interact with water. Mass is the amount of matter in an object, and density is mass per unit volume. Blocks of the same volume with different masses will have different densities. A less dense material like foam has a large volume for its mass, causing it to float, while denser materials like metals tend to sink.