1. Explain why the cold water and hot water in Part 1 moved the way they did within the tub of room-temperature water. In your explanation, be sure to compare the relative densities of the
water at each temperature

Cooling a substance causes molecules to slow down and get slightly closer together, occupying a smaller volume that results in an increase in density. Hot water is less dense and will float on room-temperature water. Cold water is more dense and will sink in room-temperature water.

the answer is b & c i believe : )

c (diamond),

sio2 (quartz)