Final answer:
When a mineral breaks into cubes, it is showing Cleavage, which is breaking along planes of weakness. Fracture refers to irregular breakage, not along weak planes. Thus, the correct selections related to the described breakage are A (Cleavage) and B (Fracture).
Step-by-step explanation:
If a mineral breaks into cubes when struck with a rock hammer, the two properties we are observing are Cleavage and Fracture. Cleavage describes the way a mineral breaks along planes of weakness, resulting in smooth, flat surfaces. Since the mineral in question breaks into cubes, which is a geometric shape with flat surfaces, it demonstrates cleavage.
Fracture, on the other hand, refers to a more irregular breakage which is not along the planes of weak bonding. Therefore, if a mineral does not exhibit flat surfaces when broken but rather has an uneven or jagged texture, it is characterized by fracture. In the scenario described, the mineral's cleavage is evident as it breaks into well-defined cubes, therefore the correct answers are A (Cleavage) and B (Fracture), as the question prompts for both terms that are relevant to the breakage of minerals.