A cast<span> is a 3-D example of an object of the past created when a </span>mold<span> fills up with sediment like mud, sand or volcanic ash. </span>Fossils<span> can form when hard parts of a </span>fossil<span> are replaced by other minerals</span><span>.</span>
Nowadays we have much more modernized farming. There are combines, tractors and other machines. Back then they used hundreds of workers and now 1 machine gets all that done in half the time. Try googling it for more info.
