Select the correct answer.
Why does ice float on water?
A.
The temperature of ice is lower than the temperature of water.
B.
The temperature of water and ice are the same.
C.
The density of ice is less than the density of water.
D.
The density of ice is greater than the density of water.

Identify the correct relation showing that the radius r of the orbit of a moon of a given planet can be determined from the radius r of the planet, the acceleration of gravity at the surface of the planet, and the time τ required by the moon to complete one full revolution about the planet. determine the acceleration of gravity at the surface of the planet jupiter knowing that r = 71 492 km and that t= 3.551 days and r= 670.9 × 10^3 km for its moon europa.