Take this practice test under exam conditions after you have studied. Grade it yourself, using your notes and book, to identify areas you need to study further. You may find it useful to study for the exam by swapping notes and working in small groups. In class, we saw that this was not necessary, that the apparent backward loops are caused by a. the retrograde motion of the earth. If the earth revolved around the sun in the opposite direction to the direction in which it rotates, then a. the seasons would be reversed b.
Gravity is responsible for a.
One can define the distance scale in the Universe readily in terms of light travel time. This means that a telescope is a sort of time machine. If we observe an object accelerating, then we can use our knowledge of Newton's laws to conclude with absolute certainty that a. it is falling b. The existence and activities of the asthenosphere account for a. plate tectonics b. The largest volcanoes are found on one particular planet.