Step-by-step explanation:
(Ans - 4)
(a) 1000 kg/ m^3
(b)
1) sink
2) float
3) sink
4) just float
(c) New density = 2 g/cc since both mass and volume of rock are halved.
(d) Ice floats because water in solid state undergoes hydrogen bond formation, which reduces its density and it starts to float.