Answer:
Float
Step-by-step explanation:
It is given that,
The density of water is 1 g/mL
The density of a rock is 0.87 g/mL
It can be seen that the density of water is more than that of rock. The density of an object is calculated from its mass and volume.
If the density of liquid in which it is placed, is more that that of the object, it will float at the top.
Hence, in this case the rock will float.