Often times, the actual object is much more expensive to create. That's why many designers and engineers create a model to represent their ideas to a group. The model is much cheaper and faster to create, especially if it needs tweaking multiple times. Also, that model can have working parts - you could take it apart to show the inside/cross-section or have interactive sections that allow easier presentation of your idea. Those are things you can't accomplish with an actual object.
<h2><em>Well, yes and no. That's because fish are part of the food chain as well and we are above them and people have to eat (i don't like fish like that). Also, fish are innocent creatures and we shouldn't be eating them at the same time that we are.</em></h2><h2><em /></h2><h2><em>Hope this helps, sorry if not tho</em></h2>
By creating a permanent water supply
Hope this helped