The cyclist who travels 20 kilometers per hour for 15 kilometers
The first practical realisation of the metric system came in 1799, during the French Revolution, when the existing system of measures, which had become impractical for trade, was replaced by a decimal system based on the kilogram and the metre.
Answer:
caves are mainly formed by water or in some other cases limestone.
Generally, a material in solid form is more dense than in liquid form. However, an exception to this rule is water, where the solid is less dense than the liquid (hence ice floats in water)