Answer:
Mercury is the smallest and closet to the sun.
Answer:
there is 7.8 billion people in the world right now
Explanation:
A ruby is a gem not a mineral :)
I would say the topic of such a study would be paleomagnetism and perhaps its effect on plate tectonics because when the seafloor spreads at the mid-ocean ridges, magnetized stripes of rock, symmetrical on either side of the trench form and they record changes in the earth's magnetic poles at certain times so can be dated to help show the rate of spreading of the seafloor at these locations.
