Tidal heating is not important for which of the following Galilean moons?
A) Callisto
B) Io
C) Europa
D) Ganymede
Question 2
According to the Big Bang theory, how many forcesand which onesoperated in the universe during the GUT era?
A) 1 force that represented the unification of all four forces that operate today
B) 3 forces: gravity, the strong force, and the electroweak force
C) 2 forces: the strong force and the electroweak force
D) 2 forces: gravity and a single force that later became the strong, weak, and electromagnetic forces