These mars can tell the scientist that there are still a lot of things that they can not discover. The glaciation can also tell us about the alignment of the earth and not just it can tell us about the climate. That is why it is really important for the scientist to study keenly in this kind of matters.
<span>Nuclear fission is either a nuclear reaction or radio active decay process in which nucleus (the center) of an atom splits into smaller parts called nuclei. This is an extremely exothermic reaction (i.e a reaction which produces heat) resulting into release of massive amount of energy in the form of heat and sometimes light. The reaction produces much more energy as compared to a similar mass of a conventional fuel, such as Petrol/Kerosene/Petroleum Gas etc. This makes Nuclear fission an extremely dense and at times very destructive source of energy. Some common elements capable of Nuclear fission are Uranium, Plutonium etc. Though in modern days Nuclear Fission are finding application in being a source of energy (such as a Nuclear power plant), but they are also used in destructive format as Nuclear Bombs and it's one of the top most imminent threats to the existence of humanity in future (in the event of a Nuclear war).</span>
The experimental control is the standard used as a comparison for the experimental groups.
For example, you may be trying to find out how different types of disinfectants affect bacterial growth. The control group would receive <em>no</em> disinfectant whereas the experimental groups would be the ones on which the disinfectants were tested.
Hope this makes sense!