When we use water, we often use too much. We waste it. When washing cars, showering, brushing our teeth etc. Because of wastefulness, there are places that don't have the luxury of being able to wash their car well, and can't water their lawns for more than a few minutes a day.
I hope I was able to help. Best of luck.
I would say that the fishes exhibited the greatest diversity (though the brachiopods also had considerable diversity) and mostly were of the ostracoderms (with a platey or shell-like skin and no jawbone) which exhibited many varieties and also the placoderm which had gills, a jawbone and fins so was developing characteristics of modern fish.
