1) B, Not 100% sure though
2)Building a rocket is a physical change technically its not changing its composition its just changing its appearance, the fuel for it causes a chemical change, there is an answer that is more clear, Grinding chalk into a fine powder only changes its shape which is a physical change.
The temperature is held constant at (b) and (d). At these points, the substance is changing states. B is changing from solid to liquid and D is changing from liquid to gas
Answer:
1.45 is larger for density