What is the hole on top of Kilimanjaro?

What is the most recent eon of the geologic time scale and what eras does it include? How does the ozone layer keep us warm? How has the introduction of bacteria and viruses in inland lakes affected the life cycle of carp? Why is the filter paper rinsed with acetone after the rinsing with water? How can people meet challenge of disasters like Cyclones and floods? Are there any desert areas in Wisconsin? What type of bond is in a diamond? What is the mass of 0.229 mol Mg? Why hydrogen has a much higher ionization energy than any element in Group 1 does? Where were your internal organs stored after death? How much does a salt cost? What is the function of the light independent reaction of photosynthesis? Are the magnetic north pole and the geographic north p0le are not in the same location? What does aluminum foil do to electricity? Does pure liquid boils at fixed temperature at a given pressure? What are the places where the ecliptic crosses the equator are called? What two things drive out magma? Who invented the pathway problem? Why and how does water temperature affect the launch of a water bottle? What is a sensible mutation?