Which moon has active volcanoesGroup of answer choicesOur moonEuropaIoCharon (a moon of Pluto)

Why is Io so volcanically active?Group of answer choicestidal heating with JupiterIt's notIts a very hot moonplate tectonics

Which of the planets in the Solar System has the most moons?UranusJupiterNeptuneSaturn2Gravity provides the centripetal force which causes the Moon to orbit the Earth.  In which direction does this centripetal force act?In the same direction in which the Moon is moving at a given point in timeFrom the Moon to the EarthOpposite to the direction in which the Moon is moving at a given point in timeFrom the Earth to the Moon3A satellite is in a stable circular orbit around the Earth.  A small rocket on board the satellite is used to increase its orbital speed.  What effect will this have on the satellite?It will have no effect on the radius of its orbitIt will cause the radius of its orbit to increaseIt will cause the radius of its orbit to decreaseIt impossible to say how it will affect the radius of its orbit without knowing the initial orbital radius and mass of the satellite4Mercury is approximately 58 million kilometres from the Sun, and has an orbital period of 88 days.  Calculate the speed at which it orbits the Sun.7.63 km/s0.82 km/s47.93 km/s4.14 km/s

Which Jovian moon shows the most diverse terrain, suggesting a violent impact broke it into many pieces, some of which reformed it as a jumbled puzzle?Group of answer choicesEnceladusMirandaTritonIoGanymede

Which of the following planet have moon(s) but no rings?(Select all that applies)Group of answer choicesUranusNeptuneEarthMars

When the size of the lighted part of the moon’s near side is decreasing, the moon isGroup of answer choicesAnnularWaningFullWaxing