Answer:
The astronomical model created and published by Nicholas Copernicus in the year 1543 is called Copernican heliocentrism. The model set the Sun in immobile position near the center of the solar system with Earth, as well as the other planets, spherical, epicycled and at consistent frequencies around it.
Answer:
Resistivity 
It depends upon cross sectional area and length of material
Explanation:
The resistance of any material is given by
, here
is the resistivity of material , l is length of material and A is cross sectional area
So resistivity 
So resistuivity of any material depends upon area of cross section and length of material
If cross sectional area will be more then resistivity will be more. And is length of the material will be more then resistivity will be less
The answer for this would be B!!
Explanation:
Can be safer and cheaper than the real world. Able to test a product or system works before building it. Can use it to find unexpected problems. Can speed things up or slow them down to see changes over long or short periods of time.
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One with greater mass (8kg)