Hi there! hope my answer helps...i made in school it got a+ and it was in school exhibition......which was appreciated a lot
take  a cardboard and place a plastic ball on it...pate that ball and paint it like earth...crush paper and twist it in shape of mountain and just paste on earth...and paint brown ...the earth is almost done and now with black sketchpen divide earth into 2....on 1st half paste 3d sick eyes,sneezing nose and thermometer of earth and 4 cardboard do drawings of bad effects like wastage of water,health probs..,cigarette,accidents,deforestation + the most important- houses with blocks and on 2 nd half of earth paste bandage on its head and make happy eyes and  smiling face and 4 base of cardboard do drawing of good effects on paper separate sheet, as u know) and then paste the good and bad ones 3d way by ice cream sticks..if u know what i mean..

and most imp..
mark my answer best by clicking on crown below my ans which will appear when someone else will me aisa model net pe bhi nhi hoga....all the best

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*Hydro electricity dam. *Aquaponic farm *Irrigation *Rainwater harvesting *Volcano *Energy conservation *Sustainable Fishing *Working Robot.Hope it helps and pls mark as the best answer. :-)